I've just come back from the mobility road show at Kemble Airport to check out the steering wheel control assessory for my son who can't use his left hand. The control allows him to use a remote controlled keypad to control the functions on the left stalk, like signals, wipers etc. using a keypad attached to a steering wheel ****. The catch is that it costs around £1000 to fit! Can anyone tell me how it can be DIY fitted? It's for a 1997 C Class Elegance estate