Whats a decent stair carpet, good sound absorption, easy to keep clean, maybe based around oatmeal colour and how much roughly as it needs everything and then fitting

Cheap and nasty landlord stuff for £6/m2 + underlay & fitting or go to £10 and get something decent.

easy to keep clean, maybe based around oatmeal colour

I’m no shag pile expert but they sound like mutually exclusive requirements to me. My living room carpet is two years old, vaguely oatmeal-coloured, and pockmarked with mucky spots that’s going to take a Rug Doctor to sort out. My stairs carpet is dark-coloured, probably 40 years old and looks cleaner.

Pale carpet + high wear areas = bad idea. Especially if it’s near an entrance , trailing muck in from outside