BuckBuck - re bad reception - my Orange PAYG switches from Orange to T-Mobile twice walking from the kitchen through the lounge and into the hall. Before the merger, it would drop calls. Vodafone (I have an Asda PAYG) isn't any better, as it fails in the lounge. Virgin (T-Mobile, not working on Orange yet) fails in the kitchen so cannot get a text or make calls if I am down there.
Mobile coverage is very variable across the country, and the maps are aimed at people not indoors, because initially the people who could most afford them were sales staff who were sat in their cars and had a better signal as a result...
Do have Three dongle (15 GB a month for under a tenner) which I use a lot from upstairs, but downstairs it doesn't work all the time, and I'm about 10 miles south of Chester before you get to any 'real' Welsh mountains. So I am semi-rural (field behind the house) but only an hour's walk to centre of Wrexham.
Three is OK for something like BBC Radio, and downloading TV, but too slow for video from YouTube or watching snooker. Many modern mobiles (and even not-so-modern) also have wi-fi built in, so I can be down in the lounge viewing web pages on a Nokia using the router's wi-fi, and some people on MNet use an iPad when they are tucked up in bed, because the wi-fi from a landline might give them a higher speed internet connection (up to 20 Mbps where the very fastest mobile networks are unlikely to give even 4 Mbps unless you are in some big city)