No; I am describing a situation where there is a strong signal indicated, where a Nokia phone works fine, but where an Iphone does not get GPRS/3G connectivity.
So T-M's geographical coverage is nothing to do with it. They are not as good as premium-priced-Voda, but they are much better than Orange (known as Zero Range

).
Wasn't there a report recently saying the standard phone with text only operates much better than smartphones?
Well, yes, a normal phone is a better
phone than most smartphones. But that's a side issue. They should all actually function as described.
The Iphone is seemingly capable of acquiring a fault condition whereby it shows a strong signal yet incoming calls do not ring. That was the problem with the last one; the Apple shop replaced it after we demonstrated it right there in the shop.