well, and here's the thing, the GP in Lambourn on the 1861 and 1871 census was David Kennard, snr and jnr, snr in 1861 and jnr in 1871.
so, looking at the household for the Kennard family in 1861, they have 2 female servants, Mary Ann Elliott aged 23 and Louisa Malt aged 13. Louisa Malt went on to marry the Joseph Thatcher that had Annie Steptoe as a domestic servant who was the mother of Arthur Thomas Steptoe who then became Arthur Thomas Thatcher, a jockey................Louisa died as you will recall, in 1872 after the birth of her son William Thatcher.
Mary Ann Elliott , the other servant at the Kennard house, had a sister Sarah and a mother elizabeth, I haven't found her with a sister Louisa, which might have identified the 'Louisa Elliott' that Arthur gave as his mother on his Scottish marriage record. I will however just check to see if there was a Louisa Elliott around the Lambourn area in the 1860s, 1870s.