[werk_ag]

Hi Graham

Just before you start do dismantle part after part , let me give you an hint... put the TX unit four or five meters apart from the RX unit (more is even better). When they are too close, the RF link don't work, most of the times the RX units just stops receiving.
Try this and let us know.

I have also noticed that the TX voltage sent, is higher than the measured batter voltage

Can you please give more details about this?

Thanks
Werk_AG