Well it looks like Ive answered my own question!!!
After doing some paintwork on the front grill panel I decided to take the bumper off the car to do the repair.
Although the material is an ABS type it did not react the same way as other ABS plastics Ive worked with to being glued together with ABS cement.
So in the end it was a case of welding the plastic together with a soldering iron and using some spare ABS plastic as a filler.
This pic shows the paint repair in progress(red tape to protect paintwork)
and you can see damage to panel in lower right of pic.
Paintwork progresses further...
This pic shows job done,looking much better and no hanging bodywork.(car is on axle stands,bonnet open.)