Native App on Win 10 - Can't connect

Great - glad it's sorted!

Who knew that a Bluetooth device could be paired without going into pairing mode?

You mean the bootloader mode with the LED lit up? That's just there so that you can update to the latest version of Espruino - it's not really for pairing at all.

Is there any harm in storing the battery upside down while not in use so it does not drain?

If it's outside the battery holder, not at all! I tend to stick mine in the plastic case with the Puck on top, and then put the silicone cover back on to hold it all in place. It bulges a bit, but it's nice and safe and easy.

Don't put the battery back in the Puck's battery holder upside-down though!