There is a plastic doctor in kingsteignton who can fix cracked car bumpers, try the yellow pages or google to see if there is one closer.
A fairing repair kit is available from CMS for about £17. Consisting of a superglue sized bottle of powder and another of liquid and a mould into which the two are mixed in order to create missing lugs, loops or simply to join cracked parts. I did 17 seperate repairs to a cbr600 fairing usiing one kit. Doesn't work on some plastics and may not be suitable for flexible plastic.
Yes, provided it's the 'right sort' of plastic, superglue works well.
The PO of my VFR had managed to send it down the road on both sides so the fairing was a jigsaw waiting for reassembly. I'd read that baking soda added to a wide superglued joint worked as a filler so thought I'd try it; the baking soda fizzes creating a filler and, about eight years and lots of all-weather miles later, the fairing is still together.