Alas, it was not to be. Said gentleman was not in, but a kind but hapless-looking stranger who explained that the shop owner and chief bike mechanic was in hospital (nothing too serious, I hope) and no repairs or maintenance could take place for two weeks or so.
So, plan B then. I took the bike to the Bicycle Boutique - they had helped me recently with something, for free - and I've used them before. I went through my list - full service, handlebar 'grips' (dunno what they're called - the 'horns' useful for comfort in long rides), spares for the journey, etc.
The chap rang me later - the bill was a staggering £126.50!!! I said yes, after consulting with HQ. It is exactly as much as I paid for the bike, less than two years ago! But... why waste a good frame, plus don't have time to find another bike, plus loyalty, etc etc. Not the best month to suffer this waking bill, but there we go - after all, it is my daily form of transport so I must offset it against what I'd pay in, say, petrol, or tram fares.
Coast to Coast? It'd better be good...