why not put a sticky one on and see if you get a tug from plod.
I would say it's unlikely.
As far as the MOT pass issue you mention is concerned, it's irrelevant. If plod considers correctly (often they dont) the plate to fail construction and use regs then it's a fine or court.
As a classic car enthusiast, as far as historical accuracy is concerned, unless your MG is a rally replica then the plate should be hanging on the bumper not stuck on the bonnet. And...comparing an MGB in any guise to an E type?
No. just No.