Although Patricks knowledge of silver is far better than mine, can l just make a couple of points
Besides Sleath having a very intresting bio, his first mark was as a largeworker entered 17/6/1720 which maybe the one "in a cloud" in 1739 a third mark also a largeworker in 1753 he was in partnership with Francis Crump
Also he was dead and buried by 21st March 1756
He was known to have an extensive range of Hollow-ware, coffee-pots tankards cups and covers, his major works are the wine-cisterns in the Hermatige.
Would he of been a maker of flatware? l know that items do turn up after a silversmiths death but is this the case ?
My choice would be George Smith ll, he entered his mark as a smallworker (undated) before 7th August 1758.
He was also a maker of flatware such as sugartongs etc, for an example of his mark see
http://castsugartongs.co.uk/castsugarto ... ithll.aspxNigel