Yes it was a HRD. Bloke who owned this one also had another, Black Widow or something. I owned an AJS 500 single in them days.
I believe one of the Challinor Brothers from Murwillumbah restores old bikes and if anyone had a Vincent he would, (or know who has one). They have done some excellent aircraft restorations and now devote their time to Tigers. Mothcare I think is their business name.