Always good to hear the outcome!
Now, it could be coincidence ...
I thought I'd try the Jersey archives for info about James.
http://search.jerseyheritage.org/search.aspxThere is one possibly relevant result for James Brown:
http://search.jerseyheritage.org/detail.aspx?parentpriref=110025326Title James Brown Jersey Ltd
Companies dissolved 1978-1985
But possibly better for Kitty Brown:
http://search.jerseyheritage.org/detail.aspx?parentpriref=110075610Immigration and Nationality Department
Registration and Identification of Persons (Jersey) Order 1940
Irish Nationals
Title Blue registration form of Kitty Brown, née O'Rahilly, of Melbourne House, Common Lane, St Helier, born 07/06/1921
Date 1941-01-29 - 1941-01-29
http://search.jerseyheritage.org/detail.aspx?parentpriref=110075609Immigration and Nationality Department
Registration and Identification of Persons (Jersey) Order 1940
Irish Nationals
Title Registration card of Kitty Brown, née O'Rahilly, of Melbourne House, Common Lane, St Helier, born 07/06/1921
Date 1941-01-29 - 1941-01-29
(those links may not work, so just do the searches for James Brown and Kitty Brown)
You can get copies of documents by emailing Jersey Heritage (address at links).
Since the story is that James disappeared
after the war, that could be coincidence - and there seems to be nothing for him from the same period.
Common Lane is a little two-block street in St Helier, and from the google street view tour, it really is a lane (with one side mainly properties backing onto it). Haven't managed to find anything about Melbourne House.
edit - scratch that Kitty Brown. I searched the archive for
Melbourne House Helier and there were several other residents, one of whom was Philip Brown born 1913. I'll leave the info as it rules out that possibility.