If the spa type experience appeals, you might also like something along the lines of a chocolate making workshop. A colleague had one of these for her hen event and it was lovely, really civilised and nice. Plus, obviously, we got to eat the chocolate...
I'm not sure where you're located, but another option would be to pick a part of the country you'd like to visit and have an appropriate "experience" there...
So, Bath might include trip to the Roman Baths (get there early though, they've been so busy this year), tour on the hop on/hop off bus, trip to the Jane Austen centre and afternoon tea, trip to the Fudge Kitchen if you have a sweet tooth (they also do make your own sessions), blow your own glass bauble at Bath Aqua Glass, and maybe a ghost or comedy walk in the evening.
York - Jorvik, York Minster, Betty's Tea Shop (though I hear it's not quite as good as it once was), chocolate making workshop, and a river cruise or ghost walk (I'd recommend the ghost walks in York, they're excellent).
Devon/Cornwall - nice, slow pace of life, after a walk along the beach/clifftops or to a farmers' market, visit the underground passages in Exeter, enjoy a cream tea and/or a Cornish pasty or two, or a chocolate making workshop.
Or make something completely off the wall, in a nice way, like a willow basket in Somerset, or a sea glass ring in Scotland?
If you really want to get away from it all and don't mind taking a ferry/train or flying then driving (sorry, I know you said earlier you don't like heights), then Donegal in Ireland is about as remote as you can get, and there are foraging, felting and turf-cutting workshops amongst many, many others. The food and hospitality are usually pretty good too and it's rare to find a pub without live music in the evening.
Whatever you decide, hope you have a lovely time.