The late 70s/early 80s was the golden period for post-bop and free jazz vinyl in this country. Particularly fond of the Honest Jon’s branch which was down the road in Camden Town back then during my student period (echoes of Withnail ). That place had the Strata-Easts and plenty of Sun Ra Saturns in the racks (which they must have got from that elusive secret-society South London store with the bath full of bricks - apparently the only UK source at the time for Saturn) as well as Beehive, India Navigation etc. Being a poor student I was reduced to Blue Note Reissue twofers and the deletions rack, admittedly I wasn’t into free jazz. Sadly, no King Blue Notes for me..
I don’t think that branch survived the early/mid 1980s, by which time I was gone.
Last time I was there on Camden Hign Street I think it was just one Reckless store and they were closing shop. The moneyed brigade had long since moved in.