Back with you folks after my Wednesday round of drivng kids to music lessons and so on - no school in France on Wednesdays.
I only hope I can keep up with developments! To recap briefly:
Allan Robertson - we have his birth, death and marriage. He was a cotton broker's apprentice in 1891, but we don't have him on the 1901 census. It's been suggested he may have been in the US then, although he died in Liverpool. Looking for him in trade/street directories from 1890 onwards could be one avenue to follow, as suggested by Burrow Digger.
Charlotte Georgina Dale Muir - Allan's wife. We have her birth, death and marriage (obviously!). She was born at sea, and died in Texas. No more suggestions here at present
Allan's siblings - Claude and Margaret. Margaret is with her mother on all censuses, and doesn't marry prior to 1901. We haven't located Claude in 1871. By 1891 he's a Ships Chandler's Clerk. What about 1901? We also have a mystery Claude found by Liverpool Annie in 1891 - what is his profession, and is he connected?
Allan's parents - James Robertson and Mary Marshall Molison. James was born c1843 in London, and died c1878/80 in Liverpool. On the 1871 census he's a commercial clerk. Mary was born c1844 in Limehouse, London. They married in Stepney in 1866.
Robertson family - need following up a bit more! Allan had at least 2 uncles, George and John. George was a Ships Chandler and married Mary Walker XXX. How about tracing his children to see how many are linked to the maritime industry? John was a Sail Maker and Ships Chandler, and married Augusta Jane XXX. He died young, and his widow set up home with George, whose wife had died, and probably acted as his housekeeper.
Molison family - again could be followed up. Originally from Scotland, and are another maritime family. Mary's father is possibly Alexander Strachan Molison, whose household she is visiting on the 1871 census. That needs to be confirmed, and her mother identified.
Muir family - Charlotte's parents are James Muir and Charlotte Maria Ann Jenkins Wilkinson King. (IGI) James had a second wife named Sarah (1881 census), and was a sailmaker. What about Charlotte's siblings?
So we have Allan and Charlotte's parents, but no further back. When did these families come down from Scotland to London?
A few lines of enquiry to follow here, plus anything else relevant you can think of!
Rambler