I have asked my friendly contact within the SSR (my wife) for the actual size and will let you know Andy
I think he knows what the size should be.
It sounds like he's planning to make them slightly smaller, perhaps to fit in a particular place, and wants to know whether anyone will ever check.
For what it's worth, I've never heard of anyone having their numbers measured.
Pete
That's the official line and that's what the original question was about!
Can't imagine getting done for it.