Thanks Keith. A little more info on the EPAS system factory fit on later 3.7 Roadsters, presumably Vauxhall derived and optional on Plus 4 of same era.
The electrical connections are relatively simple just four wires on matching connector. Main direct battery power via 40 amp fuse. Ignition switched activation via engine fuse 18. BCU supplied speed signal decoded from CANBUS, and ground. Interesting that its speed sensitive. I recall others complaning their's wasn't but maybe true of earlier versions

. Below generic layout of column electric assist steering.
![[Linked Image]](https://i.ibb.co/LDTg9zdk/eps.png)