thanks for your response, I started out with a lippo mounted where the reciever would normally go and had a miniture spectrum reciever (of an electric car that was working fine) when the problem occured. The loss of binding occurs only when the motor is running and i believe the vibrations may be causing the problem.
I replaced the lippo with a standard Tm battery pack and the reciever with a normal size one.
I use my radio on a race day with other classes with no probs.

i will try and re bind with a new model number and also check the arial wire as suggested

thanks

peter