Thanks for the info
I have already drilled and re tapped the case to 3x0.3 mm. Unfortunately the crown I had was a 24-600-0 and it looks like I have fitted the wrong tube and it has damaged the crown thread .
Am I right in thinking I would need the ‘old style’ tube for the 24-600-0 and the new style for the 24-603-0
If I go for a 24-603-0 as used on the later explorer 14270 will it look the same as the 24-600-0.