I just called them to find out what my options were. Currently on a 1 month One Plan at £15 per month. Use about 3-4GB of data, 400mins, and about 200 texts per month. Hardly ever use tethering but occasionally use it with my iPad.
They offered me:
Unlimited mins, texts, internet
4GB hotspot
0800 numbers for free
084/087 5p per min
This will still cost me £15 per month on a 30 day rolling contract. I've accepted it because I don't think there's anything better out there for me.
Hope that helps...