Wow! You people are marvellous! How you all managed to sort out this family from the many Becks around amazes me...so many thanks are due to you all.
I am certain that the marriage registered in Shardlow is the correct one...no offence CarolW...as Jeannie's family (mum, dad, Jeannie and 4 sibs) moved from Banchory-Ternan in Scotland to Foremark Hall, where dad became head gamekeeper and where the family was based for many years - there and in other parts of Derbyshire and Leics.
The newspaper article shows why Dorothy was exhibiting with Ernest Townsend (the same surname as her mentor can be no coincidence, surely): good find Cath! I shall pop that little snippet into the site (naturally acknowledging your part in it, Cath).
Joseph had been a chauffeur in London when he and Jeannie married; I presume they moved out of London when war broke out; after all, Joe would have been 58 by then so too old for service. I haven't found him in WWI at all; going by his occupation, I would imagine he would have enlisted in the Army in transport of some sort.
One of the most interesting things was when I had a look at the 1935 Electoral Register on Ancestry; I checked a few of the years before then: from 1923 to 1930 incl. he lived at 3 Carlton Mews; in 1931, he lived at No. 2; in 1933, he lived at 4 Carlton House Terrace; and then in 1935 had once again lived in No. 3 Carlton Terrace. Having looked at it on Google Maps, it is a VERY expensive building these days. I am assuming, going by the fact that it is a mews, that many of the well-to-do housed their cars and their chauffeurs there.
Thanks to you all for your input. I shall poke around on and off until I find a few more bits and bobs but I know now a little more about our artist.
Off now to pack - wee break to Berlin and Dresden tomorrow!