Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
First, let me state this.. I have no legal background, therefore I have no knowledge of whether the trip logs on your navman would be admissible. So I can only speak from a technical angle.
It is possible to recover the trip log for that trip.. If it wasnt too long ago, if you havent used the navman for a lot of trips since then, and if its still saved in your memory.
What you would need to do is download and install the navdesk software that matches your model of navman from this page.
Then, you would need to go to the reports section and view and export your mileage and trip data.. This wont work with all models. But if your model is one it can work with, page 16 on this document will help show you what Im talking about.
This is something I can try and do for you, as an additional service I can connect to your computer, install the software and try to export the data. I know the process, but I cannot guarantee that your Navman will work with the mileage reporter ( you didnt mention the specific model ) and if its been a while since the trip was made I cannot guarantee that the data is still on your navman.
If you would like me to try and connect via a secure remote session to see if the data is there, Id be willing to do so as long as you understand the limitations to success that I mentioned above.
I strive to provide great service, and greatly appreciate a rating of excellent ( 5 stars ) selected and submitted below this answer or at the top right of the screen. I always answer follow up questions.
Senior Technician and Network Switching Systems Operator / Maintainer.