You don't say on your profile where you're form Nick. Anywhere south of Birmingham just take a walk along a river, you're bound to come across a huge clump of Norfolk reeds somewhere. You need a lot to sort the wheat from the chaff, so to speak.
I had a contact years ago, a chap from Cambridgeshire, he bought a load of stuff off a one-time float maker. He parted with quite a bit of stuff for a small price and I still have a lot left. There was peacock quills, crow quills, porcupine quills and what is a good alternative to Norfolk reed, Sarcandas reed.
It's straighter, stronger, and casts better, but in the end you can't beat a bird quill for flying. It's what they were designed for.