Thanks PaulS & John Philip,
I kind of thought that perhaps the one in the Hadjamach book is on the small size, and mine is slightly on the large size, and the target size is somewhere like 6 1/2" then as- a hand blown piece, this must be within tolerance. I assume pattern book hasn't been found to confirm what the target size was?
It certainly has quality about it and a huge ground out pontil and it's almost almost flawless.
Lorraine's site is working again. Off for a proper mooch, as we say up here!