Hi,
I repaired a hole in my PVC fencing with a fibreglass kit from Halfords for repairing car bodywork. Took a bit of fiddling but it looks fairly good after it's been sanded down (wear a face mask!!!). Only other option I checked out was to fund a sheet of PVC at the tip and cut a bit out larger than the hole and stick it on with superglue. I tried it without sticking it and it looked a little ugly. The fibreglass worked for me.
Have fun!!
Denis Langley, July 2009