logo.
Here is a front view
and a back view.
.
The anode is welded and has has two letter-box holes.
,
which has a distinctive hole in the centre of the locating, centre pin.
If we look on the glass, low down, near the base and usually on the opposite
side to the label we find a number etched into the glass
This kind of marking is found on all the Mullard made valves I've seen.
It is very hard to fake as the etching can't be scratched or rubbed off.
If anyone knows how to decode these numbers please tell
me