Hi T'other JJ!
I have BT, never had a problem, but I think EE or possibly Vodaphone have good coverage. I've overcome the problem of keeping regular contact at home by carrying a Garmin InReach Mini, so I can text every day if I want to.
Hope that helps.
Louise

I believe Vodafone has slightly better coverage as a result of a deal done with the emergency services some time ago to provide better coverage in the more remote areas - can't quote a source, just anecdotal.

A SIM for an Isle of Man provider will allow full roaming which will use any available network and you can pay in GBP.

Hope this helps.

Andy

JJ aka JJ

As expected the mobile coverage in Scotland tends to follow the main Trunk roads.

The best mobile coverage map I have found is on the OFCOM web site ... ofcom.org.uk.

Just follow the instructions to reach coverage the map, you will have to enter a postcode (I used AB35 5YN for the Fife Arms in Braemar).

You can then scroll/zoom around the map for each of the four main mobile phone operators.

It's not perfect but it will give you an indication of where you may or may not get a signal. However local anomalies may occur.

If you must get a signal then, as Louise has mentioned, an Inreach Mini will be needed

I use a telephone that uses the Vodaphone network, ASDA mobile, although other supermarkets do exist.
My phone is used only for contacting mission control so it normally is switched off. I have always managed to obtain a signal at my contact locations.
Coverage areas can be verified online.