Tour of Windsor Castle, Bath and sunset at Stonehenge

if in summer the sky isn't dark until after 10. Do you hope for the tour to take you to London so late?

Even if you find a tour that does these places in one day, don't do it. You need a lot more than one day.
However, if you can find one that does Windsor Castle and Stonehenge, no problem.

I have done the Stonehenge inner circle and Bath tour--I would definitely not want to add in Windsor to the tour. I wish I had had more time in Bath, but I am still glad I took that tour. The Stonehenge inner circle part was in the evening but it was also late September that I was on the tour. I really appreciated getting to enjoy Stonehenge without the crowds.

We did the Salisbury and Stonehenge Guided Tours with Pat Shelley in September of 2017. It was the sunset, inner circle tour. Lots of historical information on the burial mounds and a visit to a larger henge. Walking up from the stream thru the field as the pilgrims to the site once did was so much more moving and interesting than just walking around the perimeter of the site with hordes of people. Worth the cost in my opinion.