erHello Julia,
While I'm mostly trying to get to as many faraway places as I can at the moment, I do also look at what's available in the UK. The walking trips JY do would be something I'd do if I could fit in.
A few years ago I did an art tour of NW England with another tour group which worked well for me. However, my issue is organised UK trips feel very expensive for what you get - so eg last year I organised my own short break in York booking 4 nights at a Premier Inn. Whilst I will pay a bit of a premium, sometimes the cost just feels too steep. I don't know if JY can take advantage of some out of season deals with hotels to keep costs down to make the cost feel bearable.
That said I live in London and I would like to see more of Scotland, especially the ancient sites right in the North, some of the Islands, the castles, etc. I had thought of organising my own trip, and using some short term tours to cover different areas, even found a tour group Rabbies, to do it with. But unlikely to have enough time to fit anything in this year, so if JY can put together something interesting for next year would look at that.
There are many other areas in the UK I would look at as well, especially including gardens, stately homes, architecture, heritage railways or experiences - eg. food tours, stained glass making etc.
Katy