I edited my other post to include Dorothy's surname - sorry about not including it before.
It was Dorothy Churchill with Catherine Churchill and they were both going to 42 Westfield Grove, Yeovil although on the outgoing UK passenger list it indicated that Dorothy had stayed at 33 The Avenue, Yeovil.
I did a couple of searches and it looks like Dorothy was the wife of Edward's brother. There is a passenger list for the Montnairn which departed from Belfast and arrived in Montreal on 25 Apr 1926 that has Charles Albert Paine Churchill, 29, born Crewberne, England who was going to join his brother, Mr. E.F. Churchill in St. Catharines, Ontario. Travelling with Charles were Dorothy Eliza Churchill, 24, born Teoril, England and their children John Armstrong Churchill, 4, born Armagh, N. Ireland and James Bruce Churchill, 2, born Clogher, Co. Tyrone, N. Ireland. I think Teoril is likely supposed to be Yeovil but the person who typed out the passenger list couldn't read the writing or made a typo.
It looks like Charles and Dorothy married in Ireland. I found a marriage in the Ireland, Civil Registration Indexes, 1845-1958 database at the LDS Search beta site for a Charles A.P. Churchill who married in Monaghan in Apr-June 1921. Unfortunately they don't give the name of the spouse in the entry but using that information I found a marriage for Dorothy Eliza Beare also in Monaghan in Apr-June 1921. Strangely both have another entry with the date Jul-Sep 1921 as well.
Jacquie