Jess:

All the British cars with DC generators were positive ground. Both cars and motorbikes. They didn't go to negative ground until the DC generators were replaced with AC generators, "Alternators" if you prefer the term.

And in fact, the Lucas electrics were really quite good except for one small part of their production: Lucas never made a switch that was worth a #$%.

My last Limey was a Jensen-Healy, that I tried not to drive at night. It was not in the least uncommon to be going down the road at night and have the lights turn off all by themselves. I kept a jumper wire handy to bypass the lighting switch, but I had to crawl under the dash to attach it.

By the way - a lot of the British motorbikes didn't use Lucas - they had instead BTH magnetos and Miller electrics.

Bill.