Fortunately however there were many original units still in place in other parts of this unbelievable building, these were as I later discovered the fantastic Sceptre.
Before looking beneath the top plate I squintingly spotted a makers mark on the shoe (our old friend Mr Adams) as you may be able to see in the picture below. This was helpful because there were no makers marks on the plates themselves (or so I thought).
Interestingly and to my delight I did discover on the reverse side of the top plate a pristine example of the makers mark, it receiving no wear is as crisp as the day it was manufactured as can be seen below.
I know not why exactly the plates have been reversed, possibly to stop advertisement, but I can see the countersinking for the screws is on the other side, so this reversal was obviously intentional and not simply a mistake by the original fitter.
Here are a couple of links about the Hall and Freemasonry in general for those wanting to know a little more.