I can say 100% it is not Jochen Hippel, the manual is wrong. If you check the credits in game it says by Sound-Images, I ripped the music for SNDH (located at $4c96a) - it is the normal Sound Images driver used by Tony 'Tiny' Williams.
On the manual it is clearly stated that the musician's name is Jochen Hippell (for Atari ST). Chris Hinley did the programming.
The music is not by Jochem Hippel as credited here (although he did a lot of music conversions for Hewson games).
According to SNDH archive the music is by Chris Hinsley.