I've bought a few items from France of late stamped with "BBC Library". They'd obviously been stored in a similar way as you could see where the plastic had reacted with the vinyl, rather like the old Polydor inner LP sleeves did to LPs.
I got some good stuff from the old Thames TV archive sell off back in the nineties, but the major record dealers had prior access and any great stuff was auctioned supposedly though I didn't manage to get into this despite queueing from an early hour. The last Wembley record fair had another TV company (I think) selling off their archive, but only got an "I'm gonna miss you" Coral DJ copy for £60 from a local dealer who'd been there.