Some time ago I made a fairing repair using Poundland nail varnish remover. It takes a long time for the acetone to chemically melt the plastics, but I would recommend this method. It can turn the plastics white (not an issue if hidden from view), and it is chemically re-bonding the pieces together. If you can be bothered, do that.
You can also put shavings of the similar plastic into a bottle of acetone to make a repair goo that is chemically similar and should give you a good repair.
It's the hidden socket part of two pieces of fairing joining - I haven't got the bits of plastic that broke off, so I'll probably bodge this one. I just want to stop the rattle!
Some time ago I made a fairing repair using Poundland nail varnish remover. It takes a long time for the acetone to chemically melt the plastics, but I would recommend this method. It can turn the plastics white (not an issue if hidden from view), and it is chemically re-bonding the pieces together. If you can be bothered, do that.
You can also put shavings of the similar plastic into a bottle of acetone to make a repair goo that is chemically similar and should give you a good repair.