The control board, now out of use following the Bletchley PSB's closure at the end of December last year, is seen complete with various annotations and notes. With the closure of the box control of the signalling has moved to the anonymous Rugby SCC. A short article was published that covers the closure of the box and the wider resignalling at Bletchley can be found here....
https://www.yumpu.com/en/document/read/51677628/bletchley-signalling-solutions - however, beware of the pop-up ads!