I see Benson and Northolt had similar figures for 2100-0900: 47.0 and 47.6 respectively. Brize Norton had 29.2 for the same period, and Heathrow 19.4.
The low has formed further SE than originally anticipated, hence the south-eastward translation of the warning area. We (the Welsh Marches and West Midlands) were in the firing line originally, so I'm anticipating a lot less rain today now.