Bri,
Like Darren I am assuming these are the newer water-slide type. They have a thicker film than the old varnish affixing type. I have only worked with the latter varnish type, and a pair I applied to my Mark 3 petrol tank posed no problems.
I have not tried this, but how about using hot water? Or failing that, very hot water? It might make the film more compliant.
-Doug