Waterline Music was - and indeed still is - a London-based recording / production / promotion company; it has a website here. It issued at least one record on its own label in the 1970s, an eponymous four-track EP by Folk Rock band Traitor's Gait (SPLASH-1 EP; 1979). Other recordings were released in the following decades, up to the present day, though they seem to have been few and far between. Splash-2, Traitor's Gait's 'Poor Old Willie' single, didn't appear until 1981. The highest catalogue number I have seen so far was SPLASH-11, a CD by Ceilidh / World band the Flying Chaucers.
Copyright 2009 Robert Lyons.