Sorry for the late reply guys exam blocks a bummer

So from what i can tell battens and batten material is rare and expensive so i have two options:
Butcher two five metre sails (one shown next to RS6 in pic) and join the smaller battens to make larger ones or;
Use some of the bamboo branches from my neighbour which suprisengly are the right width, light and seem to have enough flex.
Personally would rather not demolish the small sails as they are perfectly usable just old so maybe experimenting with bamboo battens would be a laugh at least and incredible windsurfing sail design breakthrough at best

?
Cheers Harry