Small group day out tours?

I was wondering if anyone had been on a small 'day out' bus etc Tour that they particularly loved - thinking of small villages with enough time to do a bit of sightseeing. I've been to most of the major attractions outside London , though would consider the Cotswolds again, or some hidden gems you might have experienced. I have been on the London Walks tours outside London, and those are great, so I'm just looking for some others that might be of a similar nature