We went to Northumberland in September. Didn't stay at Haggerston but not too far away.
We went to:
Alnwick Castle & Gardens (Highly recommend)
Bamburgh Castle
Seahouses
Holy Island (not worth going to be honest) cost a fortune to go around the castle & walked around in about 20mins. Just a load of Edwardian furniture. Was really disappointed.
You can get a boat ride to the Farne Islands to see the Seals.
You have Berwick & Alnwick for shopping.
ETA: For Alnwick Castle & Gardens, buy the ticket online before you go. You save 5% & print out the ticket. You don't then need to queue when you get there. The tickets were £25 each (for both Castle & Garden) but when you get there you can 'unlock' the ticket which means you can go back as many times as you like within a year. It's a doable drive from Teesside to go to Alnwick for the day.
thanks very much for the info hun....I will get the ticket and print before we go what is there? x