To disturb this stoveside reverie, just mention the word "planners" or the twee restoration of country cottages. Swan is a master rebuilder of dilapidated properties, this one included, but his approach is, to say the least, iconoclastic. These borderlands are rich in cottages and farmhouses, but he believes their individuality is being lost through a combination of inflexible building regulations and over-reliance on the spirit level. "It's quite horrifying what's going on. Our vernacular housing stock is being impoverished in the name of restoration."
Restorations typically end up with the installation of too many windows, all with the same glazing pattern, walls straightened, steep staircases made "safer" and door lintels raised to minimum heights. "I have talked to people who were actually in tears about what has happened to their house because they have no idea where to get a builder who can reproduce an old plaster panel. They're not flat, but a skilled plasterer will just produce a perfectly flat panel."
The perversity of the planning system was exposed recently further south in the Forest of Dean, when the owner of a Victorian stone cottage was ordered to replace the 1960s pebbledash rendering he had painstakingly removed. English Heritage and local planners agreed the pebbledash was ugly but seemed set on having the cottage restored to the state it was in when listed in the 1980s. "It comes down to what is historically accurate. Originally the house would have been covered in some sort of lime render," says a defensive Richard Stagg, head of planning at Forest of Dean District Council. Only as the absurdity gained publicity was the compromise of limewash mentioned.
To appreciate Marc Swan's argument, duck out of the low door into the yard and take a long look at the farmhouse he and his wife Tia have converted from a ruin to a dwelling that defies categorisation. Unkindly put, it combines the drunken perspectives of crooked houses once popular in seaside fairgrounds, with the age-worn facade of a heritage museum piece.
But the house at Brierley Hill is deliciously genuine. It lies at the foot of a quarter-mile track, overlooking a wooded valley and a tributary of the River Lugg where Herefordshire abuts Mid-Wales. Even under mist and mud it hints at Arcadia. A 17th-century two-up, two-down forms the uphill head of the house, with an 18th-century barn reclamation reaching to the lip of the valley. The roof of the weatherboarded barn appears hopelessly bowed, a wild switchback of corrugated iron, but beneath it is Tia's comfortable craft workshop. One simply has to bend double to move between the fabric-cutting table and the drawing-board by the end- gable window.
It would have been a humble sort of place. The soil is thin, the shale bedrock is visible around the base of the house, and in places within. The only record the Swans have of its distant past is in the construction itself - and here there are clues dating back a good bit further than the mid-1600s. The apex of a "cruck" frame dominates one end of an upper room. Such bowed A-frames were the basis of ordinary dwellings in Tudor times, a hundred years earlier than the previously assumed age of the Crooked House. The massive timbers rest on the shale, with one leg scorched by its proximity to the bread oven.
Marc Swan bought the house and seven acres of poor grassland for about pounds 7,000 in 1978. It seemed a high price. An end wall had fallen away, and sheep were using the ground floor as a shelter. Marc camped in the 19th- century granary as he made the place habitable according to his own vision. To talk of a plan in the drawing-office sense would be quite wrong. None exists. It would be a nice piece of mischief to ask an architect to try a professional plan of the house. There's barely a right angle to be seen.
"I'm fascinated by structural collapse in vernacular buildings," he says, leafing through a collection of photographs where tiled roofs billow like sheets on a washing-line. "People take over a house in a bad way and straighten it up. I am very interested in trying to retain parts in the shape they've taken over time, otherwise it ends up like a new building."
But that doesn't mean the Crooked House has been preserved in aspic. A surprising number of the features that look at least as old as the Tudors have been Marc and Tia's creations, though the materials used are often ancient salvage. So a stairway twisting up to the two bedrooms at the 16th-century end, where the Swans billet bed-and-breakfast guests, is in fact built into the gap the sheep once used. At its foot is a toilet with a bucket flush, installed to spare visitors either a night-time trek to the 20th-century loo at the barn end, or the rustic charms of a two- holed earth privy below yet another set of stairs.
Marc and Tia point out five sets of stairs, all of which would give a building inspector palpitations, and keep a sixth secret. In addition there is a drawbridge which lowers out from the back of a cupboard in the upstairs "pink drawing room" and gives access to the garden. Contrary to all appearances, this rear appendage to the house is pure Swan. Floors ripple and there is an alarming joke structural fissure beneath a window. On the ground floor is a traditional dairy, in which everything from the leaded lights to the elderflower and other wines in the fermenting jars has been made by Tia. From the garden, the whole stone-built extension is lurching to one side, an effect accentuated by the woodwork of a dovecote bristling with old sparrows' nests.
To pass from end to end of the ground floor is to make a journey through culinary time. At the head is the 17th-century kitchen, where for years Tia cooked stews, casseroles and apple pies over an open fire. "It certainly wasn't fingertip control," she says. The capacious chimney, with its blackened beam and space within for smoking a pig, is an original feature. The venerable colony of pink-flowering houseleeks thriving on its stone exterior is said to be proof against lightning.
Two steps down is the 19th-century kitchen where B&B guests will have breakfast at the parlour table in front of the Eagle Range, made by the extant firm of Alexander Duncan of Hereford, and salvaged by the Swans from a house in Leominster. An antique sideboard and shelves are loaded with local crockery, and by the side of the range is the mouth of the bread oven which Marc reconstructed. With so many natural shades from the woodwork and rippling red-tiled floor, applied colour is minimal; limewash between the ceiling beams and a washed-out pink on the walls. The same pigment - "raddle", normally used for marking sheep and bought from a farm merchant - has been used in a stronger mix for an uneven terracotta on the exterior.
Step down again, and there is a 20th-century kitchen, its modernity obscure among the clutter of cosy domesticity. Both the fridge and the telephone are behind wooden doors; the oven is a Rayburn and the sink is a rare milk cooler - an ancient rectangle of hollowed-out slate some 6ft long.
The Swans would doubtless have qualified for all manner of repair grants, but Marc knew that the conditions that would accompany any offer of cash - maybe raising beams, adding windows to correspond to floor area, and sticking to a planner's idea of authenticity - would be anathema. "It certainly wouldn't have looked anything like this," he says.
The Crooked House has been not so much rebuilt as organically regrown. The chaos of roofs may contain more corrugated iron than heritage-approved tiles, yet the place oozes the integrity lacking in so many copybook-restored cottages. Though Marc muses on producing a book about his work, he is no evangelist. The most effective way of getting his message out of the fold in Brierley Hill may be through the paying guests. Perhaps architects, builders and fastidious specialists from planning departments and heritage bodies should be sent there for a weekend.
For details of bed and breakfast at the Crooked House, send an SAE to Tia Swan, c/o The Hat Shop, 7 High Street, Presteigne, Powys LD8 2BA.