Receiver is powered by a 14.8V lipo, which alos drives the GR02's, through a 6V ParkBec.

I will give the batteries a good charge, test that, then change TX as well. I have the one that came with the Spektrum originally but it doesn't failsafe [The problem at Tech-Check last year] and another Orange receiver.

And yeah, I have a few pics of 540 on my phone and just spotted how close it was!