OK, finally, issue solved (yesterday afternoon). 😀
I would like to thank in particular, Christopher_G, Martin_Sm and Danni # for all their help in resolving this.
[# I hope I spelt your name correctly Danni. 😊]
And for what it's worth, I have just tested this at home to confirm it's operational in WiFi calling mode, (ironically right now I can just get a weak phone signal on the EE network - but for test purposes I used the manual network selection and selected another provider to effectively turn off mobile (cellular) on my iPhone for the purposes of the test).
This time I could make test calls (confirming it is now indeed routing over WiFi), before re-enabling EE and Auto Network selection afterwards.
So what was the issue then ?
Turns out, we were all sort of on the right track, almost from my opening comments & the post title. Basically the calling plan I was on, did not support WiFi calling.
Having given Christopher more details (by PM), he handed this over to his colleague Martin, to look into. Martin called me later on my work landline, to explain the issue was the plan I was on (as an ex-Orange plan) did not support WiFi calling. Then he spoke to his colleague Danni in contracts to work out the best (proper) EE plan to switch me over to get WiFi Calling but keeping the plan costs similar 'ish. Danni then took me through the plan change initiated by a SMS message to switch over to the new contract - all on the same (landline call) initiated by Martin. Great service everyone, thanks again.
For the benefit of anyone else, who may have experienced similar issues, my iPhone is now showing "EE WiFiCall" on the top LHS of the screen, as the network provider.
Thanks again all - issue resolved.
