Hi Neil the best way of driving these older lathes are with a intermediate shaft and two belts as the top speed is less than 1000 RPM as the bronze spindle bearings limit that. A motor was originally mounted on a cast iron base sometimes with a treadle and gear. I have an M Type and have a little handbook which I can email to you if you send me a message with that address if you want it as it has information on early models and can help with setup etc.
David