The books by Graham Wheeler appear to be the source for most of the basic UK ale recipes. Its interesting to notice that between the publication of Brew Your Own Real Ale At Home in 1993 and the updated version renamed Brew Your Own British Real Ale last year (2009) all the Maze has disappeared from the recipes.
I suspect that this reflects what is happening in UK commercial brewing, apparently Wheeler gets lots of good firsthand information from brewers/breweries and this is reflected in the changing recipes he presents.
Similar for Invert Sugar, I dont think many brewers go to the extra expense, unless they are looking for specific colours or flavours from the darker versions.
MHB
Bribe
Galaxy is very high in B-Glucanase; its not much different to other base malts when it comes to Amylase. The distinction is fairly important, if your adjunct is torrefied the high B-Glucanase isnt much of a matter for concern.
M
BOG
Just use white sugar as Sugar has a 100% yield to get the right amount of sugar:-
Maze has a potential of about 70%, if your mash efficiency was say 80%
Mass of Maze X 0.7 X 0.8 = Mass Sugar.
M