Thanks Carole,
Yes they had 8 sons and I have details of them. She was Betty Threlfall married to Robert Whittaker. She was christened in 1776 October.
He died in 1836 and from the Records she died in May1842 and I think she was living with the Whittaker's in Dolphinholme then - "died at Dolphinsholme, place of abode" is in the records at Lancashire RO. She is not on the census in Dolphinsholme though in 1841 - it has been checked.
I would have thought that she would have been with one of the children - probably forgot to mention her !
Thanks a lot anyway
Neil