Pretty much anything they have done together with Nigel Clarke is worth checking out - Thief Lord, Will, first Kleine Eisbar movie (very difficult one to find these days) and Kleine Vampir especially are all fine orchestral scores... their solo efforts are a bit more complicated (especially in Nigel Clarke's case who has several albums of his modern concert music available)....
Btw, Michael Csanyi-Wills also released collection of songs at the end of last year, which is quite interesting...
