Eric, Good to hear from you and yes, I have your Gellings (thanks very much).
I'm just beginning to look at Marg's info and the Braddan references.
One thing I see is your John Gelling b 1718-1784 Onchan md 1739 Braddan Catherine Killey b?--1770 Onchan

There is another John Gelling & Catherine Killey in Braddan
Braddan Burial Record
John Gelling 90 Ballamillagh buried 29 Sep 1812
Catherine Gelling 94 B.Milliaghyn als Killey buried 1 Mar 1806

Marg is working on a joint will of the above--not transcribed as yet.

Both of you think that John 1740 is son of "John Gelling and Catherine Killey".

The Braddan records have a lot of Gellings of Ballamillagh (various spellings). This may prove to be one of many keys to opening up these lines.
They are VERY confusing!!