Bugger, that's a damn shame. Hate having to re-work stuff.
Did you concrete directly over the floor boards or on top of some fibro sheeting? I ended up having to use a flexible rubber joint thing for my shower at one stage due to constant movement in "P" class highly reactive clay...
Looks like it's going to be a great journey. Master bed includes a fire place, WIR and sleepout? Nice.
Will you be turning it into a share house later on? There are a butt-load of rooms downstairs. Anyways, keen to see your progress. Good luck.