Stop Press - full mileage now computed.

I take it all back - the GPS was not in a sulk, nor was it an example of built in obsolescence -  it was just missing a fully charged battery.
This means that I can now publish the full mileages for each year and the grand total - you can see these on the map but, to save you a click or two the full mileage (in nautical miles) was:

                                        2125

As it took  us  3 years, that's an average speed of about 2 miles a day!