crushed my S16 before i even produced my V5

[Danny Wideboy]

Bona fide motor traders need no v5 when bringing an end of life vehicle to a scrappers/dismantlers. It was them who dropped it off and not you.
So unfortunately, yes, it is legal.
Shit for you and almost not worth wasting time over.
If it was me I would ask you speak to the person who said you could remove what you wanted from it and ask them a few questions. Don't expect too much but you may get somewhere /something.