A well done
epoxy job should last all but forever on iron, if maintained.
Well done means grinding the iron to white metal and rolling on 5-6 six layers of hard
epoxy (West style). Fill, sand and
paint to taste.
Each year repeat the process for the area surrounding any dings.
All R19s have steel keels and the racers get decades of use out of a properly covered keel (especially after paying for professional fairing...).
PS - that said I still don't understand why a generally good quality builder like Beneteau saves money using steel for keels...very stupido IMHO...it's one of those weird European things (sorry Alex...).