Not only are the lights expensive, so are replacement bulbs, according to post on another forum that I frequent.
being an Engineer, the poster found an alternative for £6 from a DIY store, instead of a lot more for the "genuine article"
Apparently, the great cost is because of the higher colour temperature of the light, (ie "whiter")
So you pays your money and takes your choice.
Another week, another Tory MP sex scandal!
To think that London, or anywhere else for that matter, does not belong to any one demographic