URGENT Advice please - Erratic headlights problem

I have an irritating headlight issue on my 360 Modena, the headlights (both low and high beam) work fine, however after a few miles of use the problem starts. Under heavy acceleration, or normal braking they either flicker of go dead totally, this also happens at speeds above 80mph. The problem is not constant and the headlights do not stay off. Scenario – I pull away from a traffic light and accelerate strongly, the lights go dead, once I slow down or cruise at a constant speed they come on again, or I will be driving on bumpy road, the speed gets near to 80mph and hey presto they go off, slow down and they come back on. Now as you can imagine this makes for very difficult fault identification as you cannot check things out during these scenarios. What I have done to date is –

· Checked all fuses and relays (including tugging, bashing and wiggling the connectors while the lights are on – cannot reproduce light failure)

· Checked all connections in the steering column
· Checked all wiring onto headlights

We are travelling to France this weekend in convoy and will be doing some night driving, I am not happy with the possibility of being without headlights in the dark French countryside as you can imagine. My local specialist has said ‘sure bring the car down and we will have a look' – but as I know, they could look for hours and like me find nothing wrong. Could it be a speed or movement sensor for the suspension or ABS that has gone faulty that could cause this (only item I can think of that is speed or acceleration sensitive).

Any advice or ideas from someone who has actually had a similar experience as to what to check for next would be much appreciated (i.e. I appreciate replies from ‘soon to be owners’ or 'when I am old enough to own a car' types but really need a solution soon guys.

Thanks