Photos of the issue would help. The only experience that I have with fog lights and spoliers on the MGF is on "elsie":-
which I am led to beleive has one of their spoilers fitted to the front. You experience interests me as "Elsie's" front bummper needs replacing and it will be far cheaper to buy a new replacement spoiler that try to remove this one as it's not only bonded but rivetted in place.
According to the chap at the body shop these "pattern" spoilers are not quite right and one has to fit them centrally as otherwise there is a 1/4" gap one end so one has to centralise this so there is a small gap either end. This was not done by whoever fitted this one and the gap is on the N/S. You can see the reason for the bumper needing replacing in the top photo the huge crack across the top of the bumper. It had previously been repaired/filled but has split again. It will probably be a M99 one that will replace this spoiler on another bumper when we get around to it!