Rimmer's have genuine and aftermarket here:
https://the75andztclub.co.uk/forum/s...41#post2788241
But before spending money put a code reader on the car, if it's the sensor playing up it should flag up a fault code.
And try the business with the rev needle while cranking, does it move? I've read many owners including this one post 5
https://the75andztclub.co.uk/forum/s...d.php?t=263168 mention it. Would be good to know one way or the other if this simple self test works.
Regards