Paul Lincoln was never a fully blown heavyweight. Mid heavyweight, possibly even light heavyweight looking at opponents under his own name. Worked in Southern England for Dale Martin
But looking at the earliest Dr Death appearances,
July 1959 against welterweight Roy LaRue in Derby
Sept 1959 against lightweight Pat Kloke in Livetpool
November 1959 against middleweight Terry Sparkes in Hull
Makes me wonder who was the original Dr Death?