Thanks for the help, but with access set to the /24 block and write set to the pool members IPs, xenserver won't create the SR at all "There was an error trying to create the NFS storage repository - check your settings and try again"

With access left blank (giving read access to all in the subnet according to the docs) and write set to the pool members IPs, I get the same thing. Pool master is the only member connected after the SR is built, others are 'unplugged'.

I'll admit to being a xenserver noob too, maybe I'm missing something on the xenserver side...