In reply to Thugitty Jugitty:
I first tried to resolve this problem with OS in June 2022 and sent them screenshots of the problem so they have been aware of this for something over a year now, and at the time of my initial discussions with them they couldn't recreate, or didn't seem to understand the problem I was having, and after some to-ing and fro-ing they closed the conversation unresolved.
I agree with others that the easiest work-around is to use a highlighter, but they should sort this issue!!
However another work-around is to set your line colour, thickness and opacity, and save the route. Then when you have selected the print area and scale etc., in the print process take a screenshot. Then Crop the screen print to include the area you need, and copy and paste it into a Word Document and print it. During this part of the exercise you can add the route name and distance if required in a transparent Text Box.
Then if you want to print the route details and way points etc., go through the normal print process in OS Maps, but omit page 1 from the pages to be printed.
It used to work ok on the previous version of OS maps, which I had been using since 2016.
Post edited at 21:21