Go on Twitter and complaint to Honda UK and link it with Which?, HonestJohn , Etc.
To be fair, the other dealer will want to see it before they can make a claim. But I am surprised that the first dealer wouldn't change it for you as they get money from Honda UK anyway for claiming warranty work! Can you speak to the dealer principal and ask him or her to act upon it?
Unfortunately, the days when Japanese manufacturers being good at customer service have long gone. I think Lexus is good but others are all the same, depending who you get.
Peteo48, likewise, no thanks VW! My parents and I had 4 of them and their products were terrible as well as their impotent customer service!