Cossie, SHG still has a touch of Vinnie in him, although thankfully less imposing.
As I sat in the waiting room one of the drivers made me feel welcome (and even offered my a coffee) which was an extremely nice touch and took the edge off. As for the feedback, the sole piece of information that I can recommend to anyone, which unfortunately is a cliche, is to be yourself. There are no trick questions, they are not trying to catch you out and there is no magic formula. They are not going to show you the door if you can't recall how much Network Rail are budgeting for line improvements between Ashford and Ramsgate, but they are looking at the bigger picture. They will be saving you the time in the long run if they do not think you are the right man for the job.
Moral of the story: Honesty at the expense of a "right answer" is valued tenfold.
Still got my fingers crossed! All the very best to everyone facing interviews, let us all know how you get on.