After having a rethink about the photo I mentioned as possibly being a younger version of Susannah Maxton I realised that it was probably highly unlikely as 1840/41 would have been too early for a photograph of that sort. It was then that I found out that Susannah's step-daughter, Henrietta Maxton, daughter of husband Samuel's first wife, Henrietta Burrows, was living in London in the early years of her marriage (1879) and that time frame would put the photo in the same time frame as most of the others I have of the Maxtons. Susannah would have been in her 30's which would be fairly close to the age of the woman in the photo. A couple of the Maxton descendants have helped me immensely with information and other photos but it seems neither of them have a photo of Henrietta so we are still working on it.
Cathy tells me that the photographer - Edward Seeley - was in Notting Hill Rd, London from 1873 to 1875 so that narrows it down to before her marriage, age in photo about 28 - perfect! BTW that large blob on her nose is on the photo not her :).