My wife and I did the London/Paris trip last May. There were several families in the group, but the Junior Adventurer stuff was a minor sidelight at a few of the locations. I haven't seen the video you speak of, so I can't reference what is being shown.
For example, on our tour of the Louvre in Paris, the Disney guides took the kids who were 12 and younger on their own tour. The rest of the group went with the local guide through the Louvre.
As you are touring around, the Disney guides do make an effort to spend time with the younger kids interacting with them to keep them interested. But, this had no impact on how the tour is conducted.
Sites like Westminster Abbey, Tower of London, Eiffel Tower, Louvre, etc. are not selected as places specificly for kids. I would characterize the trip as being very adult oriented.
Although, one funny moment, was when our local guide in London was very graphically going through how the public executions took place. The Disney guide was waving her Disney sign frantically at him as she was looking to see how many children were around. There were none.
The kids who did travel in the group were very well behaved and seemed to be genuinely interested in the sights.