Seems CWOP is interpreting your data differently from Weather Underground
http://www.findu.com/cgi-bin/wxpage.cgi?call=CW7488!Woking&radar=***&units=metric&last=24
From CWOP: Rain last 24 hours 9.70 cm
More details here:
http://www.findu.com/cgi-bin/wx.cgi?call=CW7488&units=metric
Note the line at the end of the 5th:
20170605225711 12 205 9.7 32.2 0.10 3.00 0.61 93 993.9
You can see that CWOP is doing something funky with data interpretation.
https://www.wunderground.com/personal-weather-station/dashboard?ID=ISURREYW4#history/s20170605/e20170612/mweek
As of this moment WU is reporting 0.77 in for this week, which is equivalent to past 24 hours, which is 1.96 cm
Since Rachio is getting data from CWOP, you are stuck with their interpretation which is almost 5x that of weather underground. If you believe that weather underground has a better interpretation, you could port the data to pwsweather for free and use that. More info here (link)
Cheers,
Gene