Well, as the owner of a p7, a Bianchi racer and 4 1980's bmx bikes, and a semi regular reader of stw, I've never heard of Thread Stopping Compound either.
And as a sweeping generalisation, people who spent less than a fiver on their new car (apologies, I'm sure Kia's have moved on in terms of build quality since the Kia Pride was the cheapest, but insdisputibly the nastiest car for sale in Britain), tend not to spend £100 on a Continental Tub? (tube?).
I bought from the c2w scheme, a Bianchi from Halfords, from their defunct Bikehut branch in Dorking, in, er, Surrey, and the staff were both excellent, and helpful. They were happy to let me out the shop on £1500 racers just to get a feel for the right size before I ordered my bike, (as They don't do Bianchi, they obtained it for me). When I;ve been in there casually on a sunday pm, they showed interest in my vintage 80's Diamond Back Silverstreak BMX (a classic I'll have you know), and as the shop was full of high end bikes, must have had an ability to put them together.
Ok, the local car parts superstore primarilly selling kids bikes and commuters might not be used to obsure products for people who spend £100 on a tyre, but then the staff at Mcdonalds will look at you oddly if you ask for Steak Tatare.