iOS 17 Live Alerts not working after upgrading to an iPhone 15 Pro!

After upgrading my old iPhone 12 Pro to iOS 17 I enjoyed using the new feature that it promoted as now being available to all without needing a Fitness+ subscription, the Live Activity for a Bike Rides.

After upgrading to an iPhone 15 Pro and going through the upgrade / data transfer process this feature does not seem to be working on the new iPhone!

The notification and ability to bring live stats to full screen does not initiate / appear on the iPhone 15 as I start a Bike Ride in the Fitness app on my watch. The Watch and Fitness app do still record the fitness activity successfully, I'm just missing the head-up display on the phone mounted to my handle bar as I start the ride. An obvious life saver, as it meant not having to let go of the handle bar to look at the watch as I had to do up until iOS 17!

Am I missing a new multi-layered / potentially conflicting setting that the iPhone 15 brought to this situation, such as privacy or focus? Live activities is ON in the Settings for the Fitness app and toggling it did not seem to help. The Fitness app is also enabled in the focus profiles I use.