Move cover page colour and blank coloured end page to doc-specific files. That way output where the colour isn't appropriate, such as Nook or the newly introduced A4Lulu output (which is the A4 book but with white cover page and no end coloured page, and so suitable for using as the content on Lulu, where the cover is separate) can omit the colour.

X:1
T:Sloe, The
S:Nick Barber
M:4/4
Q:140
K:D
A2| "D" d3d d2 "A" e2 | "D" f2>e2 d2c2 | "G" B2A2 BcdB | "A" A2>G2 "D" F2A2 |
    "D" d3d d2 "A" e2 | "D" f2>e2 d2c2 | "G" B2A2 "A" B2c2 | "D" d6 :|
|: A2| "D" B2A2 F2>A2 | B2A2 F2>A2| "D" d2c2 "A" c2B2 | B2A2 "D" A4 |
"A" d2c2 c2e2 | "D" e2d2 d2f2 | "G" f2e2 "A" B2c2| "D" d4 d2 :|