I'm confused. The layout of the hardware switches is fundamentally different between ANSI (the US one) and ISO (all the european ones).
You see a normal UK keyboard has an extra switch near left shift key, and the double sized enter, etc.
This also means that the two keyboards need different stabilizers.
How do you expect a set of caps to transform a US keyboard into a UK one?
Switching between UK and any other Euro layout is easy peasy, but US? Nope.