I attended this tour with my son last week and we both got a lot from it. There's not a huge amount of walking, the pace is slow (I'm disabled and I had no issues), but the tour still packs in a lot of information and sights in the two alloted hours.
A convivial guide - Russell - ran the tour in our case, and he even managed to keep my teenage son interested and off his iPad for two whole hours, no small acheivement!