Hello Kathboon
I'm a little puzzled, I'm afraid

You say that your aim is to find their descendants. As PeeJay said you will need in that case to find out who they married and/or when they died. However you do say that you will need to look at the church registers at Woodhorn. But this is only likely to help if you are going backwards - trying to find who Thomas and Dorothy belonged to.
I did find Dorothy at Seaton in 1901 with several of their children. (Joseph was Head of the family aged 20). However Dorothy was a Widow. I did notice that there was another Thomas Moore but married to a Mary J. Moore with a number of children with names similar to yours.
If we can help further, please, do ask.
Regards
Reiver