I agree ... I don't know why they have not fixed this well known issue ... there is a fix on the FFR forums which involves modifying the light ... basically reconfiguring the inside and cutting a groove in the clear plastic. Since I was modifying mine for LED lights it was not really that big a deal.
I believe the mold for the FFR MkIV is derived from an original Cobra (Dick Smith's car). I have no idea where the earlier versions came from. The MkIII is the last year of the perky butt and the radius of the front wheel wells were not correct, ugh. I think they are on the Mk IVs. As for the license plate to fit, it worked fine for my MkIII. Is it the placement of the latch, light, or both not correct?