Just a thought, but it might be worth looking round a few scrappers etc to see if they've got any painted bumpers in your colour.
I got rear bumper for £30 (and mine not a common colour), was a 20 min job to bolt on. might save all the hassle of preping and painting. donor car was the same age so it was even faded just right.
I'm sure the paint jedis on here will be able to sort you out if you go down that route.
