I had the same problem - the speed was spot on but the flare was the problem - I did nots of landing but the problem was the flare, with the same results you mention but not too much bounce (the speed being right).
The solution was found when the owner of the flight school, a retired USAF colonel, on hearing of the problem said - when you're about to land (the flare) portion the view out the window should look like it does when you take off - this fixed the problem, I rotated in the flare aggressively after that and no more problems - the stall horn going off was something I'd been trying to avoid, niw I flare with it hooting away, they are calibrated a few kts abive the stall it turns out.
It has got to be a little difficult if weather prevents training but as with everything lots of practice is the trick no matter what the mechanical silution to the problem