Hi
There is a tree on A**y for this family which suggests this on the 1871
RG10/2123
5 St Andrews St Plymouth
William Howard Head 50 Carpenter Sandford, Devon
Caroline Howard 50 b. Totnes
George 19 Mason b. Kinsteignton, Devon
Mary 14 Shop Girl Torquay
Jane 7 Plymouth
Anne 1 Plymouth
The same family is on the 1861, mistranscribed as Heward
RG9/1444
Can I also say that although George claims to be born Devonport, that doesn't mean anything, he was too young to remember at the time.
One of mine thought he was born in Kent, but he wasn't that was his brother, he was born in Wales!
So you could be right about the Cornwall connection, but I can't pin him down there either.
Good luck
Jacqui