Activity Pairing.
I have a new Phone.
Been through set-up during which my watch (first generation) was unpaired from my old phone and paired with my new one, after which the watch seems to be working correctly with the new phone except for 'Activity'.
The Activity app on my phone tells me I need to start using the Activity app on my watch and to set up Activity on my watch.
So far as I'm aware the Activity app on the phone is being used. I've tried restarting both devices and toggling some of the Watch Activity settings in the Watch Utility on the phone, but none of these actions have helped.
My last phone was a 6, so the set up on the X was a bit new to me, rather than setting up the phone by choosing a backup, the new phone detected the presence of the old phone and chose it's own method of set up, I assume this used my iCloud backup and hence maintained my historic Activity data, but until I see it I'm a bit concerned it might not have.
Apple TV (4th generation), tvOS 11, 2012 Mac Pro (10.13)