ECG app missing on your Apple Watch? I was provided this fix

I got a fix for this from senior support within the health department, I received an unexpected phone call at 9.45pm last night in the UK. It turns out it’s a known issue where your iPhone and your “newly paired” watch appear not to sync with the ECG app especially if you have set up ECG previously on a previous watch, when you go to set the ECG app on the health app on the iPhone you don’t get prompted, the only fix currently is to reset all settings through your iPhone by going to general, reset and then reset all settings unfortunately this resets your wallpaper/brightness, Face ID, wallet and other small things that need setting back up but this does then allow you to go to the health app, browse, heart, electrocardiogram (ECG) and the option to set up ECG is there. A pain of a fix really but hopefully they’ll be a software update to rectify this in due course.

Before performing this because of the importance of the health features and Apple having certain protocols to follow I would recommend contacting Apple health support but this does fix the problem or certainly did for me