These are the fixings holding the trim panels in VW CADDY, PASSAT, transporter 4 & 5 they are on the rear doors, roof, side etc. For VW, Caddy & Passat. To fit push clip into hole and push centre section to secure fixing to vehicle.
I think O'Leary stock the white ones but not been able to find black ones. Probably worth giving Chris at Reliance (Chichester) a ring they may even stock them for their service work, he used to work for a Hymer dealer.