It is so frustrating when it happens to your pride and joy. We spend a fortune on maintaining our cars and then some inconsiderate driver causes damage and tries to run! This has happened to me recently, twice! I'm glad you caught the sod in the act, as I didn't. Although one came forward weeks later much to my amazement. £200 isn't much money at all when it comes to body work and I would have requested a full respray for the bumper, depending on colour match it may need to be blended with the wings too? You're fortunate that the headlight wasn't damaged as mine was.....check out the price of one of those bad boys!!
I would consider handing the cash back and contacting their insurance company or yours for professional rectification works. The last thing you want is a cheap job that you are not happy with.