Yes to checking both of those !
I keep petrol receipts and they match the 2013-14 mileage as near as poss . It's the 2014-15 that's missing . Havn't done a total fuel check yet but it's quite low , prob around 3 thousand .
I assume the main recording is stored on the speedo , but does the ECU also keep a separate record.?
As I say , it's working fine now and since the MOT , just the total for a year of 60 miles ! Unfortunately , I never look at or record the total anywhere else .
My Twin Turbo had a speedo prob but that showed up on the speedo dial too of course .