There is the Cyclaid but it only featured as a clip on motor for bicycles, built by British Salmson in Lanarkshire, Scotland from 1950 to 1956.
Then there is the New Gerrard, founded around 1922 in Scotland by ex-racer Jock Porter. Made a single 346cc ohv JAP-engined machine throughout the 1930s, closed in 1940.