I am still waiting on a reply from the Aussie distributor in relation to the wing failure.

I did some research on GP's Performance Series models. There are five mono wing models of similar scale to the Cap 232 that are part of GP's performance series. They are listed below along with the approx release date (which i have picked up from the instruction manuals - could be out abit) along with the wing joining method for each model.

1) Cap 232 (rel 2005) Single large fixed wing with single hardwood joiner
2) Yak54 (rel 2006) 2 piece wing with carbon joiner (bolt on)
3) Extra 300s (rel 2007) 2 piece with carbon joiner (bolt on)
4) SU31 (rel 2007) Single fixed wing with 2 x timber joiners + 2 x aluminium support joiners all laminated together into a single joiner arrangement. Uses an anti rotation pin in the wing join.
5) Edge 540 (rel 2008) Single large fixed wing with hardwood joiner + 1 aluminium joiners fixed each side (2 aluminium plates in total) all laminated together.

It is interesting to note that the three models that utilise a single large wing have over time used an upgraded spar/brace arrangement with the Cap232 being by far the weakest to my mind.

I suppose you would expect design development and improvement over time. I am surprised though that there havent been more failures with the joining method on the cap.