Zwift exercise not appearing in Apple "Activity"

After working out hard, my Apple Watch / Activity App says I have failed to reach my daily targets.

Looking into this I see that none of the minutes I have worked out have been added to the
Exercise total and that the active calories for that time period are a lot lower than reported by the Zwift App.

Looking further I see that on the iPhone under Settings/Health/Data Access and Devices the Zwift App is there as a registered app and that under there All categories are turned on.

Under there it says that Zwift has access to write
Active Energy
Cycling Distance
Heart Rate
Walking + Running Distance

If I then click on Data I see that Zwift has written data under Activity/Active Energy, Activity/Cycling Distance, Heart/Heart Rate and Vitals/Heart Rate (both heart rate sets of data identical)

There is however no Workouts Data.

This seems to result in the Apple watch data being used for the time slot rather than the Zwift data.

I have read that you can reorder the apps to decide which one takes precedence - however I have experimented with this and found that the Apple Watch always resets to position #1.

This functionality does work for for Polar Beat and Polar Flow - both of these apps are lower down the priority list than the Apple Watch but whenever those apps record a workout the data from those apps is used instead of the Apple Watch data.

My Setup:
Zwift app on iPhone 11 Pro (IOS 13.4.1)
Wahoo Kickr Core
Polar H7 Pulse Belt

After further searching I found this post

It suggests that there is a problem with using just the iPhone alone