Vega Elite motor mount/gear cover problem

[Toon]

I have bought a motor mount/gear cover for my Vega 201, but I have come across a problem when fitting it.

The problem is that the spur gear is seated too far from the motor plate, and the outer face of the spur is rubbing on the inside of the gear cover. Changing the orientation of the cover makes no difference, it has to be physically spaced away from the motor plate to clear the spur.

I have measured the distance between the outer face of the spur and the motor plate face, and on the Vega, it is approx 8.5mm. I have another 201 that is standard, and the same distance on that chassis is 7mm, so the spur gear is sitting 1.5mm further out from the motor plate on the Vega, which is causing the rubbing. The layshaft cannot move any further into the gearbox housing to compensate.

What are the differences between the Vega B4 motor plate and the Tamiya/Kyosho one? The header card on the packaging doesn't state which version mine is, so I am thinking maybe I got sent the wrong one?