I believe there have been cases of the word “issue” being construed to apply only to children, but only where there was evidence of the testator’s intention, which apparently you do not have. I’m afraid I have only been directly involved in a case where
the drafter was available to confirm his intention.
There is some discussion on the subject in Vol 1 Chapter 76 of Williams on Wills which may help (or not, as the starting point is still that issue means all descendants).
Diana Smart
Gordons LLP