Hi all
Well I managed to sort this out myself. Well to be honest a friend called round & he worked it out.
You do indeed need to remove the plastic inserts I referred to, they are basically plaster board plugs.
If you are not sure what a plasterboard plug is just enter plasterboard plug into your web browser, it will come up with loads of pictures.
I just carefully prized out with a thin scrapper so as not to damage anything. The joystick just needed snapping back together & tightening up.
Stewartlincoln
October 2016