Yes, I have also seen Elizabeth and Isabel used interchangeably.

I think the most likely explanation is the marriage of William Christian & Jane Kerrish 22 Oct 1681, and her previous married name not being included in the decree.

I don't think Brian can have read your transcript carefully enough - he was an absolute stickler for not introducing names which were not there. Even when a woman had named her children including their surname, and her marriage was recorded, he refused to add the name to her maiden name on the index if it hadn't been given as "als".

Thanks for your help.

Sue