It was virtually the same as the Smiths Military Flight System. A horrid contraption which was fitted to the Mk2 V Bombers. It was a capacity sapper and although it was clever when you intercepted an ILS, that was about it. It was particularly useless in the Victor where your pitch could easily exceed the maximum 17 degrees the main display could show.
If you do find out how it was supposed to work, please share the secret as I never had a clue!