That.. Might be it... Didn't get a good look.. Trying to lie on the floor with a braced up dislocated knee..
Confused as to why the shower/sink don't trigger the leak, but even the little flush on the loo does... Volume of water, maybe? In which case, hopefully it's nothing major.
I've got a leak down the outside of my boxed in internal soil stack... Only happens when you flush the loo, not when you use the shower/sink, or when the boiler drain kicks in.
Builder who has just done my kitchen took the backing panel off the enclosed loo, and all toilet joints are solid and...