I got a second hand gearbox + mechatronics for £250 - 80k on it. I needed a new box as something in the gearbox wasn't right - the mechatronics was actually fine. However, on this new one, I think there might be a fault with the mechatronics! It really doesn't like being stationary in D with foot on brake, other than that its fine.
Garage is looking at it tomorrow, and if they can sort it somehow it will mean I can release my old mechatronics for sale...