B44 Interference

[dibble34]

Hi All
I know technically this is an electrical question, but as the problem only occurs when the equipment is in a B44 I thought I would post it here.
A friend at our local race club suffers from interference with his B44 at the furthest point on the circuit (not that far).
He is using a 12x1 single brushed motor with a LRP v7.1 esc
I think his radio gear is 40mhz FM and is good quality.
If I remember correctly the Receiver is on the top bar that goes front to back with some tape underneath it to keep it off the carbon fibre.
He has tried the same electrics in a losi xx4 and had no problem, he has also tried more than one set of kit in the B44 but the problem remains.
Each week he tries it and gives up, going back to his old car which is a shame as this looks like it could go really well.
I said I would start a thread for him and he is going to try and register so he can add comments.
Any Ideas?
Thanks in advance
Dave