Paul,
Have you considered the following:-
1) Remove the estimated Fuel Consumption from your published plans.

2) Keep a log of all fuel used (to nearest 5l litres)

3) Run a competition to see who can guess the nearest with a donated prize - entry fee £2 for instance......

Paul,

Thanks for your great idea.

Yes I will have some kind of competition but I need to check on the legalities so I can remain legal.

I needn't remove the miles from the plans because they are only from outside the port at the start of a leg to outside the port at the end. There are a lot of extra bits and anyway, I am sure that I won't exactly follow the route as planned as there will be lots of things enroute that will mean I have to deviate from time to time.

I will look into it... Ta