Thanks for your reply. The PF Jones site is full of very useful information, I have yet to check whether there is any pre-wiring fitted.The easy bit that you can do from the comfort of your chair: Have a look at the PFJones install manual online….it will show you the plug that should exist (often behind rear quarter panel on passenger side) if you have pre-wiring!
The hard bit is that you have to leave your chair to look. You could stick your phone in and take a pic of the connections to save a bit of effort.