So I spent a little time with my friend asking various electronics questions for various projects I am planning. Regarding this particular project he had looked into trying to put together some form of motor unit but agrees with you [ref]Usel[/ref], that the best approach would be to try and find some form of donor unit with the motors and sensors already installed. He is then pretty confident that it would be a simple process (for him) to put together a little control board and program it. Current thinking is the current wiring that goes into the actuator would instead go into the control board and then wiring from the control board into the actuator unit. The control board would act as a simple pass through most of the time but could also send the extra singles for auto-tilt.
Do you think that any of those last 4 links you provided would physically fit inside the current wing mirror housing? I would prefer not to replace the actual housings. I would be more included to purchase one of the units that includes the wires and connector as that simplifies connectivity to a control board a lot.
If you can offer any thoughts on which of those units will physically fit I think I will order one and then my mate and I could experiment a little. £250 is too expensive to experiment and play but £34 is definitely worth a punt.