[1andrew1]

I was expecting more competitive rates from Sky.

By comparison, BT's Plusnet subsidiary has entered the market with the following competitive introductory rates:
4Gb data 1,500 minutes £10pm
2Gb data 1,000 minutes £7.50pm

VM's rates are
4Gb data 2,500 minutes £15pm
2Gb data 2,500 minutes £12pm

Sky's rates are more expensive than either of the above providers.
3GB for £15pm unlimited calls for Sky customers, charged for non-Sky
5GB for £20pm unlimited calls for Sky customers, charged for non-Sky