Ahh so you're the guy that beat me to it (even though I left about 3 pm's on Friday) lol!
When you say the mesh is a little knackered, is it just the paint is flaking, the mesh is coming away from the bumper/bent?
If so, you could just re-spray and re-glue to the bumper.
If not, find a similar mesh or mesh you prefer. make a template from card or paper and use that to cut your mesh to size, then spray. Im not entirely sure what you'd use to attach it to the bumper, some form of contact adhesive id imagine?
Hope that helps :)