The heaviest rain appears to have been localised over the rising
ground which might be called a southwestern extension of the
Peak District around Leek and Stoke with 40mm+ in 48 hours.
By contrast Shawbury had only 7mm in the same period, the
two south Manchester stations at Ringway and Woodford about
25mm, and Buxton also about 25mm. Sadly the Chester
station (at Hawarden) has a rain-gauge problem just now, so
its record is missing -- it would have been useful.

Hi Philip,
do not forget you have rainfall data available online for Chester from Rob
Bale's West Cheshire College site which recorded 2.4mm on the 19th and 4.8mm
on the 20th,
best regards,
Alan

--
Wirral, Merseyside. 53.2N 3.0W 40m amsl
http://www.wirralcam.com/