This is a very early transition model with 'HRD' scroll on tank and rockers covers but 'Vincent' engine cases.
It made in November 1949 but not sold until May 1950 when it was registered in Glasgow.
My dad's brother bought it in about 1955 and used it extensively until it was taken off the road in 1961. I have a dedicated website for the Vincent HRD marque which can be accessed by clicking on the following link: www.myvincent.co.uk.
The restoration of this is currently on hold.