Found this (PDF) while searching for something else. Generally interesting reading, but pages 46 & 47 specifically for EV bays, and this gem - recalling other people's experiences (not necessarily in Westminster):

Both Source London and Chargemaster have upped their tariffs for Central London on-street charging locations. Source London is now up to 12.9p/minute (if the charge point is capable of 22kW) in Camden,Westminster and Kensington & Chelsea. Polar Network has added electricity charges (the usual...

Hi all! I've had an EV itch that I've been wanting to scratch for years now, I built an electric bike years ago and was amazed by the torque and performance (10Kw motor on a 30kg bike). And a friend built a 300KW electric Mazda mx5, and recently I tested a Tesla P90D. The tech is incredible, no...