My Apple Watch 3 is refusing to pair with my iPhone 12
I just purchased an iPhone 12 and I am trying to pair it with my existing Apple Watch 3. The watch has been unpaired from my old phone which is now reset to factory and awaiting return to my Apple Store. When I initiate the pairing, I am able to use the 2D moving barcode to connect the two devices but then I am stuck in an endless loop with the phone saying it is connecting, then both phone and watch returning the new pairing screen.
Ideas welcome!
Thanks
iPhone 12, iOS 14