George...
The 1962 history stated of his sad end thousands of miles away: "Most poignant of all, he never achieved the long-promised reunion with his family, even to attend the marriage of his only child Gertrude". This is a little ambiguous but it tends to suggest that the wedding took place while he was still alive, namely in 1891 or before.
Also, why would Gertrude get married in West Bromwich? Assuming her home was still Hamstead Hall, wouldn't she have married in that locality?
And third, doesn't her apparent status - boarder, circus artist - seem very surprising considering the wealth of the family, at least in earlier times?
On the other hand it's surprising if there was another Gertrude Kynoch about, of roughly the same age and not far distant geographically.
On the question of love children, far be it from me to encourage rumours which damage the reputation of an undeniably great man. All I can say on this is that, first, it does seem to be an established fact, often gained from reading between the lines rather than from explicit comment, that George was, or had at one stage been, "a bit of a lad". And second, I remember listening to a conversation of some 50 years ago between two Witton blokes. They were chuckling over the fact that at one time, many years previously, there had been one or two ladies on the Kynoch payroll who were there for having rendered services other than those of cartridge manufacture - and had the progeny to prove it for whom they collected their regular allowances. Stories no doubt handed down from father to son. But then, IF that were true and IF a daughter had appeared, is it likely that she would have born the name of George's legitimate daughter, or George's surname?
Have you looked for any other marriage of a Gertrude Kynoch?
Sorry to complicate it since, after all, you may well be right.
Chris