Dennis was born June 23, 1947 in Preston, Lancashire. He grew up and attended local schools in Fulwood and Lea, Preston.
He served his apprenticeship as a fitter-turner at Thomas Dryden and Sons, Preston from 1961-1968. After gaining Journeyman status, he worked on several paper mill and power station shutdowns in the U.K.
He began racing in 1969 and continued to 1971, with his highpoint being his races in the MGP in 1970 and 1971.
Dennis left for Canada, on his own, in May, 1972. He worked at Saint John Shipbuilding, Saint John, New Brunswick from this time until it closed in 2000. At this time he began work with Steel and Engine Products (STENPRO), in Liverpool, Nova Scotia as Special Projects Supervisor, including ship repair.
Dennis married his wife Marlene in 1974, became a Canadian citizen in 1979 and has a daughter, Sara born in 1980. In the fall of 2001 he and his wife moved from Hampton, New Brunswick to Milton, on the Mersey River, just outside Liverpool, Nova Scotia.