T-Mobile are always the cheapest UK provider and they have always had the worst coverage to go with it. I'm sure most urban areas in England are now fairly well covered but here in Scotland it's a different story where many areas don't just have bad reception, they have zero signal (and no, I'm not talking about up in the mountains where it's accepted that coverage may be spotty at best).
To be honest, I'm surprised anyone was able to download large amounts of data over their network.
Don't forget the really important sticker:
No tools* left in this TARDIS over night.
*includes sonic equipment
What the world *really* needs is a good Automatic Bicycle Sharpener.