On the matter of the current hub mounted speed sensor, I've tracked it down here:
https://www.mouser.co.uk/ProductDetail/Honeywell/1GT101DC/?qs=CWSDWQMLkcfq3%252bFb5BFFKw%3d%3d&gclid=Cj0KCQiA_s7fBRDrARIsAGEvF8SBlBiGjEj7eGmndezMeLSJAmrVA5UwfiSvRQEUPtJBQe1eaH7_l6caAu_VEALw_wcB
It's a Honeywell 1GT101DC sensor.
Mouser also stock the diode protected relays which you need for modern Morgans.