Solved What Fungi is this ??

About 3 years ago i had to cut down my Silver birch , the trunk had split during a storm and the tree being so big, was very unstable.
Well since last year, a fungi have started growing on whats left of the trunk.
I have searched my books etc. , the only one that is similar is Razor Strop Fungi.
Am i right in my ID

 

It's some sort of bracket fungus, Birch polypore maybe?

 

@flounder Thank's for that, it's an unusual one, and is growing prolific fairplay