I think I might have found a slight variety in the position of the AA mintmarks on the cupro-nickel Isle of Man 50p 1997 Motorcycle Racers issue.
A general view of the reverses

One detailed view of the reverses:

In case there's a parallax effect, I swapped the two coins around, so that the coin that was on the left above is on the right below.

Do you agree or am I seeing something that isn't there ?