ah, ah , my first estimation was 160mm, so 162 mm is a good base !
the numerous photos on the net don't give little détails….
I have already buy photos , by NR of Yok , or e-bay, but always taken from the front angle !
the nigel gresley tender was interesting……it was exactly the same , or not ? it's possible to buy a drawing ? , and where ? Reeves ?