Anyway the skip thing didn't move an inch and I damaged the rear bumper quite badly, there were a couple of splits and it was loose at the side. As the front bumper had previously been damaged, once while parked by someone who didn't stop, and on the other side by my husband when he used the car.....
I thought I'd better do something about it as it made my nice car look like an old banger. So I found a local bumper repair company online and liked the pics of repairs he'd done, so I emailed him with pics and he sent me a firm quote for the repair. He came to my house with his van and his repair stuff and paint matching and a little heater to bake the paint - these are the before and after photos of the rear bumper.
Before......

After....

For that repair, and both corners at the front (which were only scraped) - £230 inc VAT.