Methacrylate MA300 from ebay £10+. Its a two part adhesive mixed 50/50. Remove traces of any previous attempts to stick the handles on. I have used a carpenters wood chisel in the past to clean up the area, but be careful. One pack of adhesive will be far more than you need, but its a very strong and handy adhesive to have in your toolchest, and so long as you plug the tips of tubes with the twin cap provided it will last a fair amount of time after being opened for other jobs that come your way. A special dispenser gun is available, but while they cost around £17 or so, you can manage without it using a couple if pieces of dowel in order to dispense more or less equal amounts from both tubes. Setting time is somewhere between about thirty seconds and two minutes, so only mix up what you need to apply a thin coating to one side and then put each handle in place. Make sure you get it right first time as you dont have too much time for a re-try.