John P. Verge wrote:
Sharp thunderstorm 1800z at Middle Assendon, nr. Henley-on-Thames, Oxon.
Rainfall lasted 1810z -1845z, quite intense for most of that period,
with visibility 100m. Rainfall recorded over that period = 9.0mm.
Thunder and lightening almost continuous. Rain stopped quite suddenly
and sky cleared 1850z.

Clearly the same storm cell as observed by B. Burton, Wokingham, Berks.


At nearby Maidenhead we had 18.5mm in that time, with roughly 15mm in
15 minutes at the peak of the storm.