watchOS 7.5 update on Watch 3 goes into Update pairing loop with no ability to delete update or data

Trying to update Watch 3 with watchOS 7.5 using Watch app on iPhone 8 Plus. After pairing and running the update (downloading, verifying) it goes back to Software update available screen. I've tried the update repeatedly. Since the update never works I have no option but to unpair and reset which I've done (reset to factory settings). These activities have gone on in a loop-like fashion. The update is 1 Gb and I still suspect that the watch is out of space but it's not warning me or giving me an option to delete data or restore from backup. I can't get to the home screen under "My Watch" to delete data or the update itself as it keeps showing the pairing screen. I can't get to settings on the watch to view data usage either. Can't find a way out of this as I can see. The watch is not usable anymore (over an update!).

Have done troubleshooting according to : https://support.apple.com/en-us/HT211283

Devices (both watch and iPhone have been restarted several times)

Apologies if this is repeated in other threads but it seems some can eventually get to a screen where they can delete the update or delete some data which seems what I need to do.