Just had a call from Clive (MDL) to let me know that whilst on a routine "Legionaires Check" in our clubhouse, he noticed that the floor tiles were soaked adjacent to the sink. He's checked it and established that the pipe to the Saniflo pump has been dislodged. He's made a temporary fix by pushing the pipe into place but it needs a permanent fix.
I'll take a look later this morning and report my findings then.
The connection from the pump to the waste had become detached, hence the vast amount of water on the floor. I have reconnected the pipework and temporarily wedged the pump tight to the waste to reduce the risk of another accidental disconnection.
I recommend that a qualified plumber take a look before further use as I'm not convinced that the original work was satisfactory.