Thanks for the info people. Planning to get some test kit of each to see on a small scale how it functions.
Ruckus is coming in at twice as expensive, so leaning towards Ubiquiti. I know it's the Business Managers preference at present (no surprises there).
The Ubiquiti company are offering Zyxel PoE switches, so for an improved system I've asked for upgrades to HP PoE units.