This seems to be the standard cross section of a services trench. For my build, I am thinking of having a single combined services trench bringing absolutely everything into my utility room so I am wondering how to to fit everything in: Why the 350 mm radius gap between the water pipe and the gas pipe? And why the separation between the other pipes? Where do drain pipes go (foul and rainwater)? Could they go in the gap underneath the gas/telecom/electric pipes/conduits? My falls w