Also only just found out when I drained our tank is the filler rotates 90 degrees to allow the water to drain from the nozzle. Always finding something new.
Good pick up - I'll have to try this when draining it out next. I keep geeting the mysterous black stuff too...
Just curious - well I can't actually remember from handover - but when you fill the flush tank, is the water level always in the flush-tank filler neck?
Even when my flush tank is empty I have water in the filler tube like there is an air lock - is this normal?