I think the problem lies with the definition of "ditching".
NTSB -
DITCHING:
A planned event in which a flight crew knowingly
makes a controlled emergency landing in water. (Excludes
float plane landings in normal water landing areas)
Normal R44 Raven, no floats, ditching in Emergency Procedures Section 3 into water
R44 Clipper, fixed and pop-outs, you don't "ditch" as you are landing on water (not in water), therefore in Section 9 Supplements the POH (boths Fixed Floats and Pop Out Floats Supplements) say:
"DITCHING - Not applicable with floats"
This is probably why it isn't "certified for ditching" as it isn't applicable!!
They are part of the original EASA Type Certificate so are approved equipment on the aircraft.
Operating floated R44's (and any floated single engine helicopter) depends on EASA regs, but also local rules (UK ANO for example), and Ops Manuals. It also depends on what category of flight, Private, Aerial Work or Public Transport.
I know that regulations for single engine helicopters with floats differs between Spain, UK and France!
Safe Operation on water has been demonstrated in 12 inch wave (trough to crest), but I do have a video of a R44 Clipper which made an emergency landing in a Sea State 4 and stayed upright.