iphone 15 / Forerunner 255 Alarm control gone

Iphone 15 Pro on IOS 18

Garmin Forerunner 255 Music software bundle 20.32

I used to be able to silence a phone alarm from my watch. It was a great little feature.

but since I'm updated either the firmware on the watch or the IOS I no longer receive phone alarm alerts on my watch.

This is a recent thing as I've only bought the phone 6 weeks ago and it has worked.

I've unpaired and paired the two, powercycled them both, no avail.

How do I get this really useful feature back ?