Monday 18 September 2017 3.39pm
There was a thread about this recently: link
Apparently there are electrical bins on the City of London housing estates, although I haven't seen them first hand and am not suggesting any non-residents should use them.
There's also an electrical bin over the river near Red Lion Square.
Alternatively you can do what my old flatmate did: just chuck everything and anything in the normal recycling and forget about it. But please don't