Can't help with electronics means, but if you have the ticket from the carpark, take it to admin, and they'll be able to identify which machine issued it. Should help narrow down search area.
No AA RAC, I’ve contacted airport by email and just waiting now, don’t get back till tomorrow evening.
I have the MY DS app on my phone but had problems with the cars set up, my app says my car is at home address.
Thanks for tip about the key fob, may be a big help.