I used to go here several times a year until 2 years ago
Gilsland Spa Hotel - an ideal base for exploring Hadrian's Wall and the surrounding countryside
It isn't really a spa - unless you count the sulphur well in the grounds as that.
I think that the age group which go will be a little too old for you.
It is more of a playground for geordie oldies.
Rooms are pristine clean and spacious, food is good, and the geordie welcome is guaranteed.
If you want to explore Hadrians wall it is a great base, being right on it and in the middle.