Thanks Les. It is available here in the UK but at a price. Ouch!!
Amazon.co.uk: Minwax water based polyurethane: DIY & Tools
I think either polyurethane or acrylic would be hard enough wearing to withstand daily use. Acrylic is used on car bodywork and polyurethane on wooden floors.
As for the highest gloss, again it would be hard to tell the difference without some kind of measuring instrument such as a goniophotometer. I doubt if the difference would be discernible to the human eye.