A short anecdote about BMW body repairs.

One of the rental companies took on a smallish fleet of E36 BMW's when current, this renter had their own in house body shop, not a bodgit and scarper operation by any means the repairs were to a high standard, but they would get body panels from their usual supplier, i bet you know whats coming doncha.

Anyway, i took a load of these cars back to Thorne reception centre after defleet, and as i offloaded a veritable horde of chaps in smocks appeared armed with clipboards, as they went round the cars inspecting them lots of chalk was used to mark off non genuine panels (bonnets and bumpers mainly) or repairs not up to standard, there was quite a to do about it, never saw any more on the rental fleet, whatever one might say about BMW they take such things very seriously.

I wonder if any private buyers on PCP's have fallen foul on returning cars if they've had accidents during contract period, or do BMW stipulate approved bodyshops only as part of the deal?

I think you'll really struggle with rejecting under CRA if the seller is not willing to.

The car is not faulty and you had an adequate time to inspect it. If you were happy with the cosmetic condition when you inspected and handed over the money then you are deemed to have accepted it in the condition presented to you.

It is clearly "fit for purpose" and not faulty so unless the seller specifically told you something not true regarding any warranty I'm not sure on what basis you'd be rejecting it.