Thanks for the information about Sandy and his parentage. My wife's gg-gf was Alexander Maclennan, born Urquart-wester-logie, Ross-shire around 1837, married Christina MacDonald in Perthshire in 1864. They are buried in Caputh churchyard. Too old to be Sandy's parents. Their son Alexander went to Co. Durham, along with his brothers, so it seems likely that the Caputh/Spittalfield connection was lost, unless Sandy came back "home". I have photos of Alex/Christina, as well as their sons.
However, Alex's brother Donald married Christina's sister Mary, and they had children, moving around Perthshire (longforgan, kinclaven ...), I don't know any lines descending from them.