With regards to the uhmwpe I would suspect that you will not be able to glue this up, as it reacts like ptfe and dose not provide a surface that allows the glue to key onto it. If the uhmwpe is thick enough I would screw it on.
In regards to the glue for the bags can't provide any advice.
Thanks Neil, Chris and Pete for your thoughts. I looked at the links and will probably try a couple of test pieces. My first one will a solvent free poly adhesive and if that fails a latex contact adhesive if I can find one. If it is not a success I will bolt on.