i must admit that I too had same difficulty as Husafreak , but I added 0.8mm ply on one side and the wheel now have enough clearance
BUT!!!!
we pay enough money on these kits that CARF should do it right from the start
I think they have excellent quality kits and would buy another but this is really disappointing issue that seems to come from the start looking at Daves bulid from day 1 and this hasn't been fixed

PITY ........
I hope someone from CARF is listening