There is a perfectly good solution: buy a greenhouse and, if possible, lay on water and electricity. I mean a greenhouse and not a conservatory, for the latter is attached to the house, so people, large and small, will follow you there. But in a greenhouse you are quite safe, for no one will ever want to join you, just in case you ask them to "pick over" plants for dead and diseased leaves, clean plant pots, or sow onion seed. Looking after a small greenhouse takes about 15 quiet minutes every day in winter, though the pleasure can easily be prolonged. With lighting, this agreeable pottering can easily be done after dark.
The other great advantage of the greenhouse is that you need not concern yourself with its appearance. They are all, essentially, utilitarian structures for the propagation and nurturing of plants as well as their display, unlike the conservatory which has to be kept tidy and well-furnished. You can store plastic pots under the staging, use as much insulating bubble polythene and fleece as you like. You only need to keep a greenhouse pretty clean, both to let the maximum amount of light in the winter, and to cut down the risk of spreading diseases.
There is so much fun to be had in the greenhouse at this time of year when the garden outside offers relatively few pleasures. If you feel you can afford to heat one to a night-time minimum of 7C, you have the chance of encouraging a number of tender plants to flower. At that temperature, you can keep the house bright and cheerful with flowering zonal pelargonium (geraniums) and Christmas cactus (Schlumbergera) and watch the corrugated, sword-like leaves of freesias elongate rapidly until one happy day in late winter when the buds burst to display the swooningly scented and colourful trumpet flowers. Seeds can be sown in January and February in a windowsill propagator: the seedlings will not suffer much of a check when you then pot them on and put them on the staging.
If money is scarcely an object, you could contemplate an orchid house. Orchids are much cheaper than they were, now that they can be propagated by tissue culture, but the greenhouse must be heated to a minimum of 10C for cymbidiums, coelogynes and the like, and 13C is needed to grow the fabulous slipper orchids (paphiopedalum). Some, such as cymbidiums, coelogynes and pleiones, flower in late winter, which is a great treat. (The RHS Plant Finder contains a list of specialist orchid suppliers.)
Yet there is still much to be said for a cold greenhouse, which protects plants from chill winds and slight frost. You can dig up and pot on hardy plants, such as hellebores and lily of the valley, in autumn, and they will flower a little earlier and, more importantly, unsmirched by mud or holed by slugs. Hardy bulbs like hyacinths, narcissi, crocuses and tulips can be forced into flower early.
Looking after a greenhouse in winter is not all plain sailing, of course. Unless you heat it to tropical proportions, plants will be very prone to attack by grey mould, and the watering must be sparing and careful. But a thermostatically-controlled electric heater will help: it has a fan to keep air circulating, even when the heating element has switched off. With that the great escape can begin.