Ok, the Man is out there right now and it looks like there's a fairly significant blockage ON THEIR SIDE () although sometimes you still have to get your own plumber out I'm hanging onto a thread of hope that he gets it all sorted out. Also means they will have to do some cleaning for us,

ETA - TMI - urgh I can hear all our pipes going glub glub glub - I bet it's all spewing out the back again