I agree, Jacobs Cottage is excellent, I was there a few weeks ago for the 1st time and look forward to going back. I have'nt been there during the day yet. I think for a large family get-together which usually extends into the bar/lobby after the meal as the chat gets going, some of the hotels would be more suitable for the younger family members.
Newpark has a playground for children & a massive reception area which has loads of seating for those who don't want to sit in the bar. I think it has a tv room as well. Nothing as bad as trying to have a chat with someone and the kids bored and wanting to go home.
You would need to check these facilities out for yourself as I have not used the playground, but saw it one day as we were going in for lunch and as far as I can remember it is enclosed so it would be safe for the smaller ones.