i put down cheap white deal and stained it a medium oak color then put on clear satin varnish, its cheap as chips and looks brilliant,and wears really well!
I don't seem to recall MDf as being particularly hard wearing or being able to contribute to the necessary 30 minutes fire resistance and may be required of your upper floor contruction depending on the design of the building.
ONQ.
[broken link removed]
All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.