In reply to Joolz:
Cassin Skywalkers? I remember them, I used to climb with a bloke who had a pair
I think the picks off the straight shafted Cassin Antares (sp.) axe would fit too.
Needlesports is usually the best bet for spare axe parts, but I'd be surprised if they had spare parts for Cassin axes, as I don't ever remember them being that popular. Were spare picks even imported for Cassin axes? As I remember you worked in a shop back in the day, so maybe you would know the answer to that as well as anyone?
Have they been sharpened so many times that it is just not an option to sharpen them again? If so I think some new axes might be in order? Go on, you know you want to!