Thanks everyone. I too hate iphones Herbie, wouldn't touch em with an extra long barge pole.
Linas, your works building probably has a shield sort of thing that won't let mobile signals through. Morrisons supermarkets do to. Vodafone score best for talk in London according to their website.
It's strange how there are dead spots all over the place. A section, only a few hundred feet, of the M62 about 15 Mike's from Manchester going to Leeds. None of the providers signals are picked up. Aliens 👽 ?
I'll look at the links. Thanks again 👍🍻