OK, having had a good look at the car at lunchtime, it is worse than I thought.
The whole spoiler is rippled, it seems very flimsey, cheap nasty fake kit!
Anyway I am going to patch what is there (maybe) but I am going to orfer a new spoiler, I know some people here had problems with a particular make (poor quality, fibreglass depth variations etc) so who shouldn't I use?
I will post something similar on the ICE/Styling page.