Easter 1970 was at the end of March and I searched FreeBMD
http://www.freebmd.org.uk/cgi/search.pl for a Samuel/Sam Jones who died in 1970 in Runcorn. Only one came up - Sam Jones born 1 Oct 1895 who died in the March Quarter 1970 Runcorn Vol 10a Page 1667
Also searching on FreeBMD for Sam Jones marrying your nan in Runcorn the only marriage I found was Sam Jones to Winifred M Kilpatrick in March Quarter 1961 Volume 10a Page 997
If correct the marriage cert would list his father's name and occupation
Kay
Edit - This may just be a coincidence but in the 1901 census this family was living in Runcorn with Sam of the right age and his father was a barge waterman??
Sam Jones 39 barge waterman b Runcorn
Sarah A Jones 36 b Stoke upon Trent, Staffordshire
Sam Jones 5 b Hanley, Staffordshire
Sarah A Jones 3 b Hanley, Staffordshire
Nellie Jones 1 b Runcorn
Sam Lydiate 30 Boarder
Peter Cannon 14 Boarder
https://familysearch.org/ark:/61903/1:1:XS68-YTJ