1990 E34 535i Passenger seat back twisting when tilting forward

[Knightmayre]

Hi guys

I have another curly one here so I hope I'm making the issue clear...
My passenger seat is twisting itself when moving it upright so that one side of the seat is closer to the dash than the other side... i.e. it looks like |\| instead of |_|

When reclined all the way back, it's back in alignment but as you start to move it the right hand motor does not engage for a couple of seconds but the left hand motor kicks in straight away which makes the seat twist.
I am assuming that there is 2 motors for the back or is something in there slipping?

I've tried brute force in the shape of a large burly neighbour with a large pole and got it almost straight but as soon as you use the electrics it goes back out of shape again.

So, my question is how can I get the seat to synchronise sides?

Thanks in advance

Dave

EDIT: Found this while browsing: http://www.nmia.com/~dgnrg/page_11.htm