I can't justify £600 on a bumper sadly
If you can get an OEM 63 bumper fitted and painted for £600 that would be a bargain - all inner parts, bracketry, impact absorbers, radiator grille and even undertray are different and alone cost more than that to buy.
Provided we're talking about an OE bumper and not a replica like on Alps's old car.
You're doing the right thing. Guess what, I don't even like the 63 bumper that much. Only fitted it out of necessity.