Hi Harv,
Thanks for the info. I think you are right about John McKenzie b 1767. That doesn't look likely.
Re Catharine McCallum, The 1816 OPR only indicates that bride and groom were of Kenmore Parish and no details of parents. An 1841 Census only gives birthplace as Perthshire unnfortunately.
On a search for McCallums birth/baptism records in Kenmore, I found 2 Catharines, 16/01/1798 of Finlay McCallum/Christian Campbell and 22/01/1798 of Donald McCallum/Christian Stewart.
I have yet to trawl through Fortingall. There seems to be a rash of McCallums in there.
Al