Thanks for all your contributions guys!
Another point that no-one suggested is that my (new) aircraft has a bl**dy great Lycoming IO/360 hanging on the front, which is quite a weight for a fibreglass aeroplane. I am now of the opinion that this extra weight makes the 'feel' of the roundout quite different than, for example, a PA28. When it starts to settle down the pull force on the stick to keep the nose off the deck is more than I have previously been used to and maybe this is why I am not pulling it back enough.
The worst thing for me is loosing 'face' after having been able to land a whole range of aircraft without problems for the last three years - we're all human