I use mine with my Starling account. Great watch, especially if you combine it with a Garmin HR belt, they give you many more stats than just Heart rate.
Likewise. Curve works perfectly on Garmin pay, and allows you to use any bank with your garmin watch. My Bank is HSBC for example - no worries!
I use my Fenix 5 Plus with a Curve card - works with any bank then.
It's been this price for months, John Lewis sold out a couple weeks back but Argos, Amazon and Blacks have it at the same price
Also garmin have released bike mounts for the fenix 6 range which makes this a good tri option if you are not too fussed about the slickest of transitions