Tom R once bubbled...
I lost a fin and a local TDI instructor found it and kept it even with my name clearly marked on it. So I wouldn't bank on getting it back. This year we have found a lot of stuff and almost every bit of it returned to it owners including a very nice watch.
Tom
Hope you know it wasn't me who found and kept your fin Tom... don't know who it was but I can make a guess...
I lost a fin myself drifting into the Daryaw earlier in the year but managed to back track a little and pick it up.
Steve