I recently bought a BMW X5 diesel sport, which I'm really happy with apart from the Audio & Visual entertainment. I bought the car with (VST) LCD's in the rear headrests and a playstation 2, which sounds great apart from the fact that its not working! The Passenger LCD is working (displays "No Signal") while the right LCD seems to be broke as I swapped the leads and it wasn't working

Can anyone recommend a good Car Audio & Visual Independent specialist that has experience of installing and repairing LCD screens and in-car entertainment systems? Ideally based in London or South East that's a mobile service. I was recommended to visit a BMW dealer..... that's the very last resort as its not mechanical.
Thanks in advance,