I added the app that you mentioned.
when the bangle.js gadgetbridge app is not connected to the watch, the watch shows in the NRC app (it does not show when the watch is connected with the phone via gadgetbridge).
each time I try to get the NRC app to connect to the phone for HRM readings, it says an connection error has occurred.
I'm really struggling to speak with NRC about this as the phone number keeps circulating me through the main switchboard through a series of unhelpful advisors. I'm trying to find out from them if there a requirement, in the interim, is there anything else I can try?