help identifying makers mark on 18ct Pd ring

I have a diamond ring which is stamped with "18ct Pd". The Pd is stamped within a trapezium shape.
The ring is also stamped with a capital 'T' within a circle, which I am assuming is the makers mark. There are no other marks or stamps that I can see.
The ring is a trilogy ring (three diamonds) and is an older style, although I'm not sure if this is an old ring (ie: WWII when palladium was commonly used instead of platinum) or a reproduction of an older style ring, which is why I am hoping to find out who the maker is.
I believe that the ring was made in Great Britain or Australia (as in the US ring would have been marked 18k PD). Ring was given to me in 2008.
I would be grateful for any help identifying the makers mark.