If you need a speed sensor.....

[Harvy500]

Griffith, chimeara, cerbera speed sensors are TVR MO631 sensors.
Hard to find and if you can, would set you back around £130.
Or....
https://www.pistonheads.com/gassing/topic.asp?h=0&...

Edited by Harvy500 on Tuesday 4th July 10:31

[Sardonicus]

Fitted two of these over the year (different cars) GKN and BTR diffs, I have one on my own car for the last 7 years + plus no bother and you dont need to run silly small air gaps for the unit to function , good guy to deal with