ok thanks. I have no idea what was fitted or how to check.
Just wondered if anyone knew what they were.
It does flick up and down and looks like the middle is off but not sure what it does.
Does it self return to the middle on a spring I.e so it flicks up or down but then self centres?
Also if the van has an overdrive box fitted it will have an OD switch so would probably solve the mystery. Look at the gearbox and check for an OD bolted to the rear of the gearbox, will be alloy coloured with a Laycock plate on it