you probably need to invest £10 now to get a copy of the Death cert, which will give you more insight into the circumstances/cause of death - with a bit of luck.

http://www.gro.gov.uk/gro/content/order_certificates/index.asp

not sure how far back the local weekly newspaper can go :-
http://www.thisiswesterngazette.co.uk/

Western Gazette, Sherborne Road, Yeovil, BA21 4YA

just remember the registration was in Blandford, that does not mean the death or burial are in the town