M&B Radio - there's a name from the past! I bought various bits of surplus-stuff from them in the 70s.
Does anyone know what happened to another of my favourites - A.H. Supplies in Sheffield? I bought a few modules for my Racal RA217 from them in the early-80s.
Another of my go-to places was "Stweart of Reading" - loads of test-gear !! Seems they're still trading....
http://www.stewart-of-reading.co.uk/
And Telford Electronics often had 'unidentified' lots of Racal/Eddystone modules/boards - if you knew what to look for. They're still around:
http://www.telford-electronics.co.uk/