Yes indeed mate. There was a great underground market on Market Street, and in there was a stall called Discount Records. They used to display 7" single covers, coloured vinyl and picture discs on the walls.
John Peel show was one of the few ways(if not only way back then) to get to hear some of the stuff sold there.
My mate took a punt on the double A side single by Armed Force, and I think I read somewhere they only pressed 500 singles.
Also bought a 12" EP by the band V2 for a bargain 50p! I put it on here if you scroll back to near the beginning of the thread.