Marcos Maniacs

Hallo Marcos friends,

Does anyone have a manual of any kind of information of the overdrive: 
Laycock L.H. type

I don't know for sure if the earlier ownwer has made changes yes or no.
I am struggling with the connection. Do I have to work with a relais 
or an extra switch on the gearbox as a protection?

Looking forward to your information.

Best greetings from the Netherlands,

Twan