Easiest way to supply it is in an A4 sheet, you can cut it how you want it then
An A4 sheet is £5 including first class post, UK delivery, not cheap stuff I am afraid, is the same stuff they use for stone chip guards of Porsches
Basically its a slightly rubbery clear film, stops cable rubs and good for chainstays as its totally clear but stops the paint getting chipped
PM me if you need some