Admittedly, this is a "sampler" tour, although it's the best I can imagine. Having spent extensive time on other visits in Avebury and Bath, there will be decisions to be made that you wouldn't have to make, particularly in Bath, where you have to move briskly just to tour the Roman baths (CAN'T be missed) and have lunch. In Avebury, the guide does an excellent job of pointing out the monuments and their archaeological significance, so you don't "miss" something as much as you don't have time to fully soak it in. The Stonehenge visit is about as good as one can be with excellent on-site explanations by the archaeologist of the significance of what you're seeing. There are great photo ops at all three places. Most "average" tourists will be completely satisfied, and rightly so. It is all a factor of what you can do from London. If you want to experience all three in depth then an overnight stay in Bath and an overnight stay in Avebury with an included trip to nearby Stonehenge would be the thing to do. But if you just want to cross these three awesome places off your bucket list, take some great pics, and have the significance of what your seeing explained by a knowledgeable professional, and do it all in one day, this tour can't be beat.