Todd and Buchanan mystery in Glasgow

[Rosinish]

David Buchanan brother of Margaret who married Colonel Sir David Davidson

Thanks Sancti,

I'm back on track now 

1891 he is still in Humbold Road, living on own means with wife Annie and family

Forfarian, this may be a fact from your earlier thought...

or that he came to own these properties in later life, and if so, how did he afford them?

Annie

[Forfarian]

1891 he is still in Humbold Road, living on own means with wife Annie and family

Ah, yes, there he is, indexed as Buchman. No wonder he didn't appear before!

[Rosinish]

1891 he is still in Humbold Road, living on own means with wife Annie and family

Ah, yes, there he is, indexed as Buchman. No wonder he didn't appear before!

Ditto, I couldn't find him either 

Annie

[sancti]

1891 census has Margaret (Buchanan) Davidson born in Kinross

Name:   Margaret Davidson
Age:   68

Relationship:   Wife
Spouse's name :   David Davidson

Where born:   Kinross

Registration district:   Newington
Civil Parish:   Edinburgh St Cuthberts
County:   Midlothian
Address:   Woodcroft

[sancti]

1881 and 1871 and 1861 have her born in Lanark, Lanarkshire

[Rosinish]

  https://familysearch.org/ark:/61903/1:1:XYKD-YTL

Margaret Buchanan b 1824 Kinross

Annie

[Rosinish]

A few in Lanark ?

http://www.rootschat.com/links/01j04/

Annie

[Rosinish]

Don't think any seem right though from familysearch

Annie

[sancti]

https://familysearch.org/ark:/61903/1:1:XYKD-YTL

Margaret Buchanan b 1824 Kinross

Annie

To confuse things further, in 1851 she gives her place of birth as Glasgow