Sorry, I wasn't suggesting they'd NEED to recharge every trip, just that the capability will be there. Having said that, don't the ones operating Bletchley to Milton Keynes get a small recharge every round trip?
I'm not sure there will be recharging capability en route; at the depot certainly, as with the pair of BYDs and two Irizar i2es they are already geared up for that. That said, Leon Daniels has been on record saying that there is/was a worry about plugging in a depot full of electric buses at the same time and whether the grid is up to that kind of draw. Presumably it has been dealt with, or will be before the BYD-Enviros enter servie.
The two Enviro400 virtual electrics for the 69s will definitely be charged 'in the field' at Canning Town and Walthamstow, however, although that is to enable the diesel engine in them to be used as little as possible, and if charging is not possible for whatever reason they can function as 'normal' hybrids, if such a thing exists...
I think the reason for the MK StreetLites require recharging at the end of each trip is that their battery capacity (being lightweight vehicles) is lower than would be possible on a heavyweight 18-tonne GVW single-decker. The concept is a good one, but the application - with the metal thing underneath which lowers on chains (!) to take charge - is bizarre in the extreme.
Volvo have shown how to handle en-route charging with the street furniture mounted pantograph, which is coming to some 7900 hybrids in Edinburgh in due course and is already in use in Hamburg. They made a huge thing of it when it was launched at the Hannover trade show last year and understandably so.