interesting post. Your rainfall figures are higher than mine at Steyning. Are you using a Met office approved 5 in dia gauge? And you may be at a higher elevation than me?
Automatic weather station raingauges are often mounted in non standard positions and readings are not strictly comparable with Met Office exposure eg look at the rain recorded on the Shoreham Beach Weather Stn site.
Here at Steyning (400metres N of the Downs at 30 m asl) in winter we can get 1/3 more rain than at Worthing on the lea side and 1/3 more than sites 2 mile inland .ie the air rising over the Downs condenses out and produces more rain and we are still in the cachment area for it. 2 mile further inland the rainfall is back to where it was at the coast. Areas north of the N Downs are a lot drier.
As an average guide over a year for 1931-60 my rainfall map gives 35-37.5 in for the Downs from Lewes to the Adur ,
35in Steyning- Amberley, 35-40in for Storrington - Winchester. Sebastian's site looks at about 37.5 in
We are often warmer at night than Shoreham Airport in SW to NW winds, up to 5c even. On foggy days down below it is often sunny on the tops.
You station must be susceptible to considerable local weather variations as well?.
This wet spell is notable for its length with little break since 13 Dec.. The flooding of the Adur and Arun floodplains is quite common and although this winter's rain has just beaten the local record since 1923 and possibly beating 1914/15 , it is way behind the Oct+ Nov+Dec total of 2000 when Oct was particularly wet. Here at Steyning we are getting less heavy showery rain from troughs and active cold fronts than places more inland.. Usually there are more deep warm sectors giving us copious orographic rain which drops off rapidly with distance from the coast.This season Horsham and Hurstpierpoint are well ahead of me in the rainfall stakes eg 20-40mm more each month.
Hurst also recorded more than me in Oct 1987 and 2000. What clouds the autumnal rain is the showery contribution. 3 times since 1985 I have experienced at Small Dole, south of Henfield, the most violent rain in all my life - probably 2 inches at least in an hour ;but 2 mile away much less. Hurst recorded 70mm that day in Oct 1987.
There is a lot of weather info in our area from 1991 back into the mid 1800's including Tottington Barn and Butser Hill but more recent local weather is difficult to obtain . I can direct you to sources of past info if you like. It might be possible to get readings from the Environment Agency
I communicate regularly with Horsham, Hurstpierpoint and Coombes (Lancing) weather stations and exchange rainfall.
A comprehensive UK weather summary is from COL (Climatological Observers Link) . The Met Office site does detailed maps.