My question regarding if there would be a live guide on the routemaster wasn’t a dig, I was genuinely curious.
If I was visiting a city and got on an open top tour to find no commentary I’d want my money back. 
If however this routemaster has no live guide/announcement system but is ran as a duplicate and passengers are given the choice, then fair enough.

And re the comment about Beamish not being for the disabled, Beamish went to the lengths of adapting their vintage yellow single decker to enable wheelchairs to be loaded into the back!