Why don't you try Northumberland?
There are boat trips out to the Farne islands to see seals and puffins, Alnwick Castle of Harry Potter fame, with tree top walks and a treehouse restaurant. There's the Roman Wall at Housesteads and Vindolanda if they want a bit of history. Bamburgh castle and Holy Island are also spectacular. When its sunny the beaches are the best in Britain, miles of velvety white sand with rock pools and dunes for dune surfing.
Local food includes stotty bread, scotch pies, excellent fish and chips, kippers and crab, soft bread baps etc.
Can't remember its name now but if you Google cottages near Rothbury, there's a lovely farm centre with a free spa on site (jacuzzis, sauna, pool, gym, etc) and the cottages are very reasonable. Also horse riding from there if they want to get a bit sporty.
And it's very near Scotland.