Hello everyone.
A quick update on the situation.
After having done a lot of searching, I wasn't able to find the part I was looking for. I asked RimmerBros whether the part they had for sale would also fit my car, but they replied that it wouldn't.
AllBrit seemed to also not have the part I was looking for.
So in the end I just purchased an old chair valance complete with switch pack and switches. The only difference is, that this part has the memory buttons on it. I am not sure whether the memory will work (I highly doubt it, you most likely need different motors which can sense the position of the drive shaft etc...), but I quite certain that the switchpack will be able to control the lumbar and base adjustment of the driver's chair.
I have taken the 75 on a few trips now and I couldn't be happier with it. It is an absolute joy to drive, its quick (some times a bit too quick...) it gets good fuel economy on longer trips with the cruise control on, and it is soooooo comfortable!
Anyway, I'll post again as soon as the part has arrived.
