just reporting back to you Klaus. I found it very difficult to deal with the front lock. The metal mechanics are the same as the rear but there are certain features of the assembly which are different. I tested, worked and cleaned the micro switches and then with great difficulty put it all back and since then (fingers crossed) it has all worked properly. The rivet holding the window guide has to be drilled out to gain access but it is fairly simple to replace it with a nut and bolt on re-assembly. Altogether, a fairly tricky job requiring a lot of patience but thank you for your help.