I agree with Heather. Evostik on both surfaces and leave for the suggested 15 to 20 minutes to allow for evaporation before bringing the two parts together. This way the plastic will not be affected long term.
If using no more nails I think it's best to make sure it's the non-solvent variety. I think evo-stick also has some solvent in it, so I'd be tempted to try Gripfill non-solvent adhesive. I used it to glue styrene based track to blue foam and can't shift it, despite trying. I was convinced it would rip the blue foam first.
Tony
Thank you for all the replies, I will pop down to Squires and buy some Evostick. I would go to my local B&Q but the car parks under 2-3 feet of water at present.