I'm not sure how you got that last sentence figure, so would you like to explain that please.
What I was trying to say is that for example a plan that costs now 20£ should cost approx £20.43 after VAT change not £20.99
My initial figure given was incorrect. I think someone had sabotaged the library PC calculator I was using.
I have now corrected the figure above.
A £20 tariff now is ~ £17.02 + ~ £2.98 VAT.
From 1/1/2011 the figures
should become £17.02 + £3.404 VAT, which will be rounded up to £3.41.
So I agree that the total
should rise from £20 to ( £17.02 + £3.41 ) = £20.43.
I did not understand from your OP that '3' were raising their prices above the rise in VAT.
If that is the case, perhaps you should make it more explicit to be clear.