I used a very large soldering iron and some cut up strips of ABS plastic to repair mine. You can't even tell it's been repaired and there is no worries about disimilar materials showing thru the finished paintwork.
The soldering iron trick is how it's doe anyway Alan. The plastic welding lads just use a fancy machine that applies the abs as itmelts the damaged surface. Sound tip, using a soldering iron and its just a bit slower than the fancy way.