A different but nevertheless relevant alternative possibility is the signal box plan as of June 1963, which appears in a photograph of the interior of the station platform box on p13 of The Eastern Around London A Colour Portfolio, Kevin McCormack, Ian Allan 2009.
There are reflections off the glass cover but the layout is almost entirely discernable save for the throat opposite the turntable entering the tunnels, which is hidden behind the signalman's head, and the very ends of the suburban platforms, behind the movements book.
The image is 2Mb which is too large to post on the forum and I see that you have only made 1 post so cannot use private messaging yet...
Either post several acknowledgements to the replies already made, so that you can use private messaging, or find a copy of the book...
Kings Cross track layout 1960’s
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