You can get 46mm piston Def calipers for solid or vented rotors. Dougal (kiwibacon) has all the relevant part nos. posted by HSVrangie in the FAQ section under Rover on Outeimits4x4.
Cross reference the part numbers with those on Paddocks website. If you get the calipers from them get Mintex pads at the same time, price is dirt cheap and they're streets ahead of anything else I've used.
Solid rotors do have some advantages over vented.
DL

