Found some basic data and a picture from this site, so i have just taken a better pic of the gun on my tube
and have it with a picture from a Duke Nuken post about a duff AW36-21 and they do look very similar to each other, some differences which could just be down to year of manufacture.
This is a new picture of the 17" tube, with the light coming in from the side i noticed some white shading where I would expect the getters to be, hence thinking it could be going to air.
It is being fed with 6.3 Volts for the heaters and have 300V via a 300K resistor between g1 and Cathode to give a measure of cathode emission, it was very low to start with and is slowly building up with time. I appreciate this may not be an indication of vacuum as that will only be noticed with HT applied and watching for the blue glow, but the best i could do at the moment.
Thanks everyone for assistance it has help me quite a lot.
The tubes need work to the aquadag as a lot is flaking away I have some on order, A fibreglass small brush will be used to clean up the pins and a few bases need re-fixing, but I believe they will be useful in the future.
Adrian