Drayton RF3/SCR fault?

Hi
Last winter my RF3 was a bit dodgy and now it's pretty much failed. Have tried resetting, but no joy. The SCR red light comes on permanently and I have had to leave it on override and operate the boiler manually. The RF3 battery compartments slip and if I push the drawers up it does seem to transmit a bit then fails, thought the display is ok. About to buy a new transmitter but thought I'd ask here first - is it the receiver or the transmitter? Is it fixable?