Thanks for your comments, chaps. I had the car over at Evans Halshaw's bodyshop today and they noticed that the force of the spoiler being cracked off has slightly deformed the top bit of the tailgate (the corners where the spoiler is bolted on have bent downwards slightly).
So he's putting a quote together and when we know the price we'll decide whether to pay for it ourselves or claim off the insurers. I don't want to lose 9 years of no claims, but if it's a dear job I might have to. And then it'll get nicked again.
I know - I'll take the bolts out and fit blanking grommets in the holes. B*llocks to the spoiler - it doesn't need it anyway! (only slightly joking)