Have you followed up the executors of Isabella's will- John Moffett, Berwick, Accountant, William James Paxton, Croydon, Draper and John Knox Weatherhead, Berwick, Solicitor. Although the other two could be her financial/legal advisors, could the William Paxton be a relative?
There is a William J Paxton on the 1891 in Croydon - 60 George Street. Aged 61 and a Manufacturer's Agent - textiles, born Berwick on Tweed. Wife, Anne, down as a Draper. RG12/590/166/72
PS - 1881 is at RG11/813/60/18
brevitas
(It's snowing horizontally in Newcastle

)