Hi there
So took the car to Birchdown to have the trotting noise investigated and some other jobs.
As soon as Andy heard the noise he was like you had a genuine belt fitted, I was like yes and he was yep some batches of belts they make the writing on them a bit to heavy and it causes this noise. He said it’s nothing to worry about but that he solves it by sanding the raised writing down, he did this and the noise is gone.
Car is in good health and they said it’s a good one, they did the other jobs I asked, Andy also checked the timing and it was a little out nothing to cause damage but it would of been a touch down on power so he also re-timed everything up. So the idle is fixed as well car is awesome.
But wanted to report back for others that the trotting noise is just the writing on the genuine belts, does not impact all but just some depending on the batch and cure is to sand writing down if it bothers you.