using resistors to reduce voltage

In the end I found 2 washers under the top mounting point of the actuator fixed it. These were not in the original design, but at least it works.

So score 1 each for KP and me! As soon as you said retro fit, I thought positioning, been there, done that got the (Clifford/Viper) T. shirts, all those years with Mk/l & ll Golfs, Polos etc. 1st rule of fitting a door actuator, test it physically first, nice easy run, in and out. Second rule, make sure neither it or its supply cables foul window mechs etc.