Spent the weekend in London.
Truly spectacular storm, Saturday night, around 10pm. Almost continuous sheet lightning, by the time each rumble died out, a new one had begun - lasted at least two hours. I watched from a 5th floor room, with (of course) lights out and curtains wide open.
Absolutely amazing. I also watched it on lightningmaps.org but oddly, whereas out in the sticks where I live it is uncannily accurate, in the middle of London it bore no obvious relation to what we were seeing. Lots of strikes showing, with the right sort of frequency, but nothing in real time that actually coincided with the directions we could see with our own eyes, 5 floors up.