If you are really interested in a spooky, informative ghost tour, then you would probably be better off doing one of the 'London Walks' tours or another tour company. A tour where you could get off the bus and see/feel the location more.
This is tour tries hard to please, but its essentially a lighthearted actor as the tour guide with another actor joining in. Whilst it drives you around London and gives some pretty basic, generic information on London's darker past, it also has the actor/tour guide acting out a subplot of the bus being haunted. There were a couple of tweens on our bus and even they didn't seem spooked or entertained by it all.
The bus is decorated well, but we were fully crammed into the bus and could barely move. (Its an old 1960s bus - charming but not very spacious). Quite unpleasant on a hot evening, with their loud speakers screaming in our ears and curtains blocking the window views.
In short, our money would've been better spent elsewhere.More