Probably should have been the first place to check...

Update:

returned home and wifi calling not working. So it appears that by previously resetting network settings to try solve it not working at home it must have turned off wifi calling toggle but the issue remains and is isolated to my home network.

What connection are you on at home? Any parental control filtering or DNS blocking of things? CG nat or actual IP address?

Tested OK for me:

richms:

 

What connection are you on at home? Any parental control filtering or DNS blocking of things? CG nat or actual IP address?

 

No parental controls or DNS blocking. DNS is set to obtain automatically from my ISP.

I don't believe I'm behind CGNAT, as I can access my TVT NVR remotely via a direct connection (not through a cloud relay service), which requires inbound access to my network.

My IP settings are also obtained automatically from my ISP.

What make/model is your router? What firmware is it using? Can you update router the firmware and have other people reported this problem or found a solution?

Issue resolved!

I think I might have disabled this setting some months back to try and enhance the security of the router turning off things that

AI said wont break anything and I just never noticed till recently that Wi-Fi calling wasn't working. 

Great result!

Always verify and take time to understand what you’re about to do, especially so if AI says do X y Z.

It's really amazing that the Telco industry has managed to make wifi calling a complex mess when other calling apps need none of this being worried about.