Some of you propably remember that there was one "mystery" part in batch of parts from my Mk.III which no one could recognize.
Now I can say this mystery has been solved!
I was thinking about the center hole and its purpose and got some idea. Today I proved it by test. Part TL14588 (which I couldnt find even in Chilwell) is new style of blanking board which we are used to see made from plywood. This last evolution is made from steel and apparently used on last types of UCs.
Happy to solve it