Treasure tag on Windows phone – Where’s the app?

I recently bought a Nokia Lumia Treasure Tag to assist me in finding my keys on the occasions I lose them.
The treasure tags came out in 2013, but I didn’t really pay them any attention. Between then and now, the Treasure Tag Windows Phone application has been deprecated (unavailable in the UK region was the error message – perhaps globally..?). Annoyingly, the apps for Android and iPhone are still unavailable.

However, after a little (a lot) of messing around with the phone (a Win 8.1 Lumia 640) the recently updated Gadgets application noticed that i’d paired with a Treasure Tag.
Treasure Tag Gadgets

After a couple of screens of initial setup, my Treasure Tag is working as expected – with Phone-tag Findme functionality working as expected and the Tag’s button also making my phone react.
Treasure Tag screen