Not the first of the type to go into service in London, but First's 4 Gemini 2 DLs are finally in service from last Saturday. But for the additional radiators in the hybrid version, the diesel version DL is virtually indistinguishable.
4 WNs are allocated to Westbourne Park, and they should all be use on the 23, in theory.
At the moment, First also has 5 Gemini 2 HEV in service, plus one DL version with London Central. In addition, London General has a HEV imminent. Arriva has 5 HEVs and 57 DLs on order. The 5 HEVs are now, as I have learnt, not due out until the end of this year the earliest, pending conversion of the 38 back to double-deck operations.