Just a little more info to add, if you don't already have it.
The 1921 Census for Barrow in Furness 51 Vernon St has Mary McQuade, a widow, aged 67 years and 10 months born Ramsey, Isle of Man.
The online Manx iMuseum Indexes have a Mary Jane Kegg daughter of William Kegg, a Joiner, and his wife Mary, baptised 29 Aug 1852 in the parish of Maughold. They were living Maughold St, Ramsey.
A variation in ages between the Censuses and this baptism, but looks like a good candidate for her.
Thanks to everyone for the prompt relies.
DonM - I hadnt thought of anything like that. Referring back to some notes, a second cousin said there were some "relationship problems" between Henry and Mary Jane according to his father & grand father and that they didnt talk to or about Henry.
CaroleW - I dont know but it is certainly a possibilty.
Garstonite - Yes and I have her birth cert. Your link to William is probably her brother.
Girl Guide / aghadowey - I thought you had cracked it but the link to the 1911 census records states he is a Catholic so incorrect.
I need to keep digging but this forum has proved very useful