Christopher,
Thank you for the idea. I have just sent an e-mail to the webmaster as you suggest.
Yes, Agnes McCalmont who married John Heaney was the brother of shop owner John McCalmont who was called 'Dummy' because of being a deaf mute. Maybe this derogatory nickname will ring a bell with someone.
A Montgomery cousin remembers going to visit John & Sarah in the 1930's but she can provide no further info.
All of Agnes' & John's siblings were born at Ballymoney, Islandmagee between 1878 & 1893 & John & infant death James are the only ones proving difficult to find.
They were also half-siblings to Sammy McCalmont who ran the Ballylumford - Larne ferry from 1953 to 1982 with Dougie Hood.
Roger