Hi Pete
If you mean the ones on the underside of the bed, and the ones to access the underfloor/boot,which look like a ring-pull; I bought some from Roy Hopwood Fasteners. They had them in different finishes and for different thickness of board. they were very good to deal with and probably not as dear as Hymer.
If they don’t have them, you could try a chandlers as quite a few of our fixtures are off-the shelf items used on boats.
Their address is Hibbert street, Whitehill industrial estate,Stockport,SK4 1NS. sales(at)rhf.co.uk.
0614296066
Those were their contact details 2014 but I don’t know if they are still in existence.
Good luck with it.
Nozzi