Another sneaky aside, but relevant as regards hearing. A few months before leaving the Beeb, I was summoned for my Bi-Annual audio check with the nurse. I'd never met her, and she didn't know where I worked. But after sitting in a chair, headphones on, pressing a button when I heard a sound...She analysed the results, showed me the graph, and said "You work with Rock musicians" (She had no clue which department I came froom!)
I asked "How can you tell?" "Well you've got a dip at about 6 Khz in both ears...Above and below that all is fine. .....Close proximity to snare drums being hit very hard....All Group 2 Studio Managers have it...It's not a problem, you're not going deaf, It's just something we recognise on a regular basis!"
Back on topi (Lol!) of monitoring. When I was at Maida Vale, we had a pair of "Boxer" speakers, inset in the Studio walls...Huge buggers...Also a paif either "Aurotones" or "NS10s" much dinkier. And, before my time, apparently a converted mono transistor radio with a Jack plug input!
The idea being that you'd do the main recording on the big buggers, to catch all the nuances, but, would then mix on the little ones. and finally listen on the modified radio, (as that was what most listeners, teenagers would have)
The intriguing thing is that, The vocals, although sounding great and sitting in the mix on the Boxers, came up in level the smaller the speaker! By the time you got to the tranny, you couldn't hear the band!
(A lot of bands didn't get this process, until I played the little mono version, and the cries of "Where's my guitar solo gone") etc.
Sorry to go on, but the relevance is, I have no idea what Bill Leader was listening on. Probably not State of the Art. The whole Leader thing was done on a half-pence from what I understand.
I still submit that Bill and Johnny Gill came up with some of most exciting and life affirming recordings in the 70s and 80s.
We are all richer for the knowledge that they achieved them.
And we are all the poorer to know that have been denied access to something like 140 LP's. All for some petty point scoring excersise.

I hope the souls of Joseph Taylor, Billy Pigg, Cecila Costello, Tony Rose and not least Mike and Lal Waterson will hunt you down in the hereafter.

Sorry for the rant...