Scott,
I'm very sorry to read of your mishap. It sounds frustrating and painful. Ebb's right, some pics would help flesh-out story on the repair. Once you have the mast off it should be pretty straight forward. As far as FRP goes, if previous work was done in the step area you'll probably need to enlarge the 'reconstruction' to include that work. At least that way you'll know exactly what was done and it be done to your standards. The beam can be handled a number of different ways and all acceptable. Someone once pointed out here that the original design worked fine on these boats for many years. You could simply replace the old with an exact copy. Or, a sandwichedly enhanced version that many Ariels have in them these days. One could even be as unconventional as Ebb and laminate a new stronger beam. He is radical.
Unfortunately this all takes time. But as you know, there is something emensly gratifying about nursing or mending a boat and making her right again.
Hope any of this helps. Tony G