Thanks for the info.
It's been a while since I did the original research via Scotland's People. Since moving overseas my subsription has lapsed so now relying on the various free resources available online and the almost exhausted credits I have with GenesReunited.
From what I can see, Euphemia is the sister of my GGF. I did some quick cross checking online last night via Freecen and I am as sure as I can be without seeing paper evidence that it's the same family. Thinking about the Jane Hamilton Howat b1840 and David Howat also born 1840, could they have been twins with the former perhaps not surviving? As mother Helen doesn't appear in the 1851 census there is a suggestion she died in the period between their birth and 1851.
I know father, John was alive in 1851 as we established he was with his sister and his 3 youngest children.
In the 1841 census, Euphemia is living with their mother Jane SCT1841/646 folio 3 Pg41 with two other Howats, Marianne and Christina, 15 and 10 respectively and Jean Dunn aged 2. The latter child also appears with the family 10 years later in 1851. Jane doesn't so I have to assume died between the censuses.
Unfortunately, freecen doesn't include later scottish censuses so I'm not sure if I can get much further forward. Any help you can give or pointers in direction would help a lot.
Again Thanks in advance.