You're right about Chattaway's score, though I still think his masterpiece is the music to "Maniac".
"Maniac Cop" is allright, but I always felt it's not quite as good as it could have been, not only because of Tom Atkin's untimely exit (I like a surprise or two, but not when they concern a film's most likeable character
).
He has a pretty thankless role in "Lethal Weapon", though his "confession scene" is one of the film's highlights.
I liked his turn in "My Bloody Valentine 3D" too, particularly his scenes with Kevin Tighe. Good to see character actors like these in modern slashers- though they'd deserve more screen time.