Thanks for all of your help, I sourced from Autodec (discs had gone up a bit) all discs front/rear and pads/sensors for £850 . Labour was a few hours (harder to get places to fit parts these days, they all say their insurance will not allow) so from a Mercedes dealer quote for £2300 it cost under half of that. Still, those strange front discs are the big cost .
Also , Autodec shipped and got through customs in days, very impressive compared the nightmare I have getting other shipments from Eu into UK post Brexit.