Well, I'll try to be gentle but, I reckon you're nuts. Do you really want to destroy those cool old decals and the neat graphics on the seat tube?
After you get it down to the bare frame, clean it up, maybe de-rust the bad parts a bit, and clean and polish the black paint with some ScratchX or other cleaner wax. Whatever's available over there. I think it would be a mistake to re-paint it and and even bigger one to have it powder coated. You might be pleasantly surprised with how it will look with a little careful cleaning and some elbow grease. Plus, is it really worth it spending that much for a re-spray and 30 quid's worth of decals?