Any sticker will come off if the surface wasn't clear of any oily or waxy coating. These may include polish, rainex, supaguard and so on. The maker of the stickers suggests cleaning with a solution of meths and water, but of course testing for damage first in an invisible place.
If anyone does have trouble, I will do replacement stickers at cost.
(£2 for the last lot - I'll see what the new ones cost once they are here).