Thank you all.
Karen, I find it best if you can roll your sugarpaste as thin as you can. ( nearly as thin as petal paste)
Leave it to sit for 5 minutes to firm up slightly! It will be less stretchy and less likely to stick.
I use corn flour for rolling out. Press the cutter in to the paste and wiggle on the board to free the letter.
I find the best way to then remove the letter is to kind of flick the cutter strip on to the work surface. A bit like you would have done with a plastic ruler when at school. (Hope that makes sense) sometimes the letters do fly across the room, but mostly this works for me!
Good luck!
Amber Catering And Cakes