Speaking of Carreras and Halfords:
I worked there while doing my A levels, bought a couple of Carreras, but once paid 50p (no sh*t), for a complete Quattro comp minus frame and fork, that's entire 1989 Deore XT II grouppo and wheels, all in top nick (insurance write off). I've still got the pedals!!
50p was a lot in them days, I was earning £1.84 an hour if I recall.
They once listed XT thumbies at £7.76 (each side) in the spares list, you could order them but never get them at that money. I think I did manage to get an XT seatpost (New) for less than a tenner once.
Oh happy days!