For those who were able to get the o2 simplicity 10 deal you can now add 500 mb for an extra £5.11 and NOT loose your original bolt on, which in my case was unlimited o2 to o2 calls
To do this call up o2 customer services and ask about adding data to your plan, if you have unlimited o2 to o2 calls this would normally be removed, but if you ask they will keep it added!
I know this is quite niche but its a good deal for those who can get it!
So now for £15.33 (VAT increase)
unlimited o2 to o2 calls
500 mb data