Depends how much they have to spend/how far they want to drive but a few ideas :
Rheged centre just outside Keswick on the A66
A good day out - Haverthwaite steam railway, onto the lake cruise up to Bowness or Ambelside - All undercover
Aquarium of the Lakes - Lakeside
Beatrix potters house/museum Hawkshead/Ambleside
Hayes at Ambelside they also have a big display of tents and other camping gear at the bottom end of the car park.
There are cinemas at Kendal & Barrow, and a much smaller one in Bowness.
I am sure there will be a Wacky warehouse type place near by, if not Ducky's farm at Flookborough, we managed to spend a day there when it was raining in early August.
Brockhole visitors centre between Windermere & Ambleside
Loads more, Sellafield visitors centre, hardknott/wrynose pass the drive is well worth it even in the wet.
A lot to do in Carlisle too cinemas, and plenty of Roman bits & bobs.
They may be able to get a day pass for Centre Parcs Whinfell Forest. That'll give them use of the pool and all that stuff, along with plenty of under cover space to keep dry.
Rheged as said before. there is a great play area called priates of penrith. Trotters world of animals is also good some indoor and outdoor near Keswick.
Walby Farm park nr Carlisle has a fantastic indoor play area.
You can get into centre parcs for the day but is quite expensive.
You could do a mine tour at Honister Slate Mine. The Hadrians wall stuff in Carlisle/Hexham is great.
Houghton Hall Garden centre has a great world in minature in side.
you could go to the upfront puppet theatre nr Jn 41. a bit further you have the Gincase near Silloth.
Ullswater Steamers or Keswick Launch. Dalemain or Hutton-in-the-Forest.
Sellafield is closed now to visitors
Some suggestions for you
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