Hi Frou,
Still working my way through census, I was looking for David Willis but not much luck, chased up the few I found but none were piano makers and I looked at marriages and then census but any spare Davids checked out in later census. Wondering when he died, his death cert would help if it showed his widow's name and his age. I see Mary Ann Willis in 1871 is still married even though husband not present. There's a death for a David Willis aged 44 in March Qu 1881 St.Giles 1b 409 which could be the one, can't see any others. You could maybe check with the registrars for his occupation before you bought it.
The Deas look promising, although David Deas was a lithographer, two of his sons John & James were Piano Makers in 1881. In 1851 David was married to Harriet (unless a mistake for Janet) both born Edinburgh or Midlothian, orperhaps he married twice. Can't find the marriage in England, you may have to post a request on the Scottish Board for that in case they married there, or look for it on
www.scotlandspeople.gov.uk - just to see if Janet was a Willis in a former life! If she's his 2nd wife the marriage should have been in England but can't find it.
Have you tried to track Mary Ann Willis in census/deaths after 1871? Where was she when little Lizzie was with the Deas?
That's it for tonight, hope it helps a little,
Barbara