Hi Mike - yes I think it is them, I have them on the 1841 and 1851 at Mill Hill, and Post Office, Belgrave respectively. By 1861, I assume Robert has died, as Elizabeth is living with William at Leicester Road, Belgrave with children, William, Selina Jane (the give away) and Frederick (aged 4M), but no wife.
On reflection, there is a Robert living at Mill Hill in 1861 (with Richard Pole as lodger - he is direct line to Yvonne who I met on RC), so perhaps Elizabeth is with William to look after the children. If they are connected to Richard, then they definitely fit into my tree somewhere, as Yvonne and I have worked out where our lines come together (In the mid 1700s!).
When I have a minute I will try to find William's marriage, which may lead to a reason why there was no wife in 1861.
Thanks again
Richard