That's because the 452s are only marginally better in the wet than the 040s, and they're both not really suitable for the Zed and this is what happens when you mix tyres.
Oh come one, this has been going for pages now and that's the first time I've mentioned anything!
Hope it gets sorted out soon fella, I think you took it quite well considering but please don't underestimate how important it is to have matching tyres all round.
No its not.
have to agree, tyres only need to match across the axle. yes its nice to have the same across the whole car, and its what i use. but different front and backs doesn;t suddenly make it like a greased otter.
as for the 452's not being adequate for the zed, they seem more than capable for the XKR.