My apple watch touchscreen just stopped working

Apple Watch Series 6 which has had no issues and was fully updated.

After the iPhone iOS upgrade to 18.0.1 last night, my watch still works, but the touch screen is completely unresponsive. Unable to enter pin, or use the screen in any way. Side dial and button both still works.

1 - I did a hard reset (10’second crown and button push),

still same problem.

2 - Completely disconnected watch from iPhone and reconnected (remember watch) still same problem.

3 - Completely disconnected watch from iPhone and reconnected (new watch) still same problem.

Can anyone suggest what I can now try to get my watch working again?