Rented flat terrible floor creeking

Assuming the carpet is fitted and the vinyl glued down, and again, assuming this is a timber "suspended" floor of planks or boards on joists below the floor covering, fixing the creaks could be a couple of days work.

I had this problem in my own home, caused by loose boards which a plumber was obviously too idle to secure after fitting central heating; quite fiddly to fix. I lived with it for four years, waited til we re-carpeted, then after removing all the furniture and stripping the old covering, I spent a whole day lifting many of the existing boards to find out where the pipe runs were and to avoid puncturing them when nailing and screwing them down again, before the carpet fitter arrived. I still managed to nick one pipe!

So you could mention it. In fact, unless they've always been like that (as in the case of an old conversion or a shoddy new build) the LL might like to know a plumber has botched the carpenty (as in my case- the most common reason). But don't hold your breath!