In the past I used 1 route TO work and another FROM work (due to adverse cambers and heavy traffic)
When asked to confirm my HTD, I provided a Google Earth plot of the route THERE & BACK and my claim for the return/2 was accepted.
Currently I claim for the fastest route as the shortest route takes over 50% more time to travel.
Fastest is 76miles return - 34mins single (quickest at 2300hrs)-45mins (normal traffic)
Shortest is 65miles return - 52mins single-92mins
Note:
Apart from 150yds outside of my house to main road....
Fastest is on County Council/Highways Agency gritted roads
Shortest includes 4-line East Coast Main Line level crossing (add 15mins at the wrong time) and is not gritted.
When I've explained, it has never been a problem.