Indeed things are not up to past standards in London as regards vinyl. The 'golden age' was probably the late 70s/early 80s with the likes of Mole, All Change, Colletts (predecessor shop to Rays on Shaftesbury Ave) and Honest Jon's had at least 3 stores (Baker St, Portobello Road and Camden Town - the last of these was particularly ). And these were just the specialist jazz places ! Those were the days before trendy fashion crap 'boutiques', useless mobile phone emporia etc. and their high rents forced everyone out. The CD era also sounded the death-nell.
Heck, in those days even places way out in the sticks like Plymouth and Weymouth had jazz stores !
'Rays' is a nice place to check out - have one of their cappucinos in the cafe, one of the best in London. Good for CDs although I've not seen anything in the vinyl racks of note the last half-dozen visits.