I pushed out the original post at around 2215 BST last night.
It was based on a bit of speculation on my part and some trajectories from the last of the visible satellite images .
As you can see from the SFERIC map thunderstorms did affect London and the SE also the whole of East Anglia as well as the extreme NW which didn't feature in the original warning.
I was a bit late on it - then again I'm an armchair meteorologist who was on his way to bed after watching a bit of telly!
It took the Met Office almost another hour to update their thunderstorm warning that excluded the SE to include the SE.
This is another example of where a broad brush approach (at least 6") works best for warnings - or in technical terms - you might as well be hung for a sheep than a lamb.
I did manage to salvage a copy of the updated warning from my phone, they are very quick to dispose of any incriminating evidence from a previous warning (probably because it could be used in any litigation against them) and they don't maintain an archive.