quick update here. It should be arriving today.
However, interesting one.
When I called up, they offered me 3 options
1 - Change to a lower tariff as I 'Can't make full use of what I've paid for'
2 - Have a reduction in my monthly bill (I'm on the One Plan with a iPhone 4S, worked out about £5 per month
3 - Get the Home Signal.
I asked for the Home signal as I'd just like to get a signal in the house, but said if this doesn't work can I get the line rental reduction... She claimed it was a one time offer, but I'll see what happens....