Screwing into thin GRP

For lightly loaded overhead applications I have had some success using hot melt glue.
Drill the hole out a bit, squirt in a good blob of glue and quickly put some tape over the hole to stop it dripping out. You need gloves to not get burns from the glue! It gives you a nice resillient, rubbery blob to drill and screw into. Obviously it only works on overhead holes so the melted glue lands on the back of the surface you are attaching to. For modest sized lightweight panels, I found it a very quick and cheap solution.
 
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