Of all the anecdotes to treasure in Tuesday's marvellous article by my colleague Simon Usborne about 100 years of Britain's intelligence services, my favourite was probably the one about MI6 moving offices, sometime during the Cold War. Before the move, the MI6 offices were shown to prospective new tenants, among whom was a party from the Russian Trade Delegation. When the security officer found out who was coming to view the property, he rushed round telling everyone to act sharpish and take the maps down from the walls. All of which is gloriously reminiscent of a sitcom little-remembered these days, but of which I was very fond 35 years ago, called The Top Secret Life of Edgar Briggs and starring the young David Jason as an inept spy.

Anyway, speaking of secrecy and official secrets, out here in rural north Herefordshire we come across quite a few military personnel, and once they tell us where they are based – at Credenhill near Hereford – then even Edgar Briggs could work out that they are probably attached to the Special Air Service. Mostly, they are very charming and properly discreet about the work they do, although at a social occasion recently we met one fellow who rather flaunted his discretion, which of course is a contradiction in terms, but his affected coyness about serving in the SAS seemed like a strategy to draw attention to it.

"I'm sorry, my hearing's shot," he said at least five times, stagily leaning forward to hear what was being said to him, although actually he much preferred to talk than to listen. The clear implication was that it was bomb-blast damage, which is not something I should be flippant about, as a man whose physical bravery extends about as far, and no further, as killing the occasional drowsy wasp with the flat of my hand. But there was something unsettling about it, all the same, not least because all the other SAS folk we have met have been such paragons of modesty and easy charm, neatly diverting attention away from themselves and showing a gratifying amount of interest in what must sometimes to them seem like matters of overwhelming triviality, such as the GCSE performances of local schools, or the form of Hereford United. These are manifestly the kind of people you would want to storm a hut in the Hindu Kush mountains should you be unfortunate enough to end up there as a hostage.

Moreover, at another recent social outing I spent 20 minutes chatting to a man who impressed me about as much as anyone I've ever met, yet without saying anything about his day job. Or, perhaps more accurately, his night job. It was only from his proud mother that I knew him to be a member of the Special Reconnaissance Regiment, a crack counter-terrorism unit also based near Hereford, though that's pretty much the extent of what even his mum knew. And even that sparse information she probably shouldn't have shared.

Actually, what interests me most about all these remarkable men – remarkable in some cases because of how unremarkable they seem – is not what they do in Afghanistan or Iraq, but what they get up to here. In particular, I'd like to know more about the gruelling challenges they are set to discover how tough and resourceful they are, because that's where we, or at any rate our few acres, enter the equation. I've been told that prospective SAS and SRR soldiers are tied up in large bags and dumped somewhere remote in the British countryside, their objective being to free themselves and make it back to Hereford without assistance from any other human-beings, whereupon they are promptly tied up and dumped again, obviously after a good night's sleep deprivation.

I seem to recall that this practice is known as bagging, although when I Googled 'SAS and bagging' what I mostly got what was information about the baggage policy of the Scandinavian Airlines System. So perhaps it has another name altogether, or perhaps it's just an urban or in this case a rural myth, but I quite like the idea of Andy McNab-types, with 'Who Dares Wins' not tattooed on their chests but engraved on their hearts, stealing through our garden late at night on the way back to Credenhill from the Scottish Highlands. It would certainly explain the occasional hen that goes missing from our chicken run, without the slightest sign of a struggle.