@ John McGough
My tariff is in store o2 35 and i get the 'unlimited' web bolt on for free.
So yes, really you should be getting it for free provided you haven't already got other free bolt ons.
On another note, o2 made good on upping my speed. they recently turned on HSDPA in Manchester around when the original story about bandwidth capping broke and after several calls to CS they have indeed removed the cap. Before i was getting about 14kbps actual download speed, testing through my computer over bluetooth, and now its up to just over 100kbps actual download speed.
I was T-mobile before and i got about 200kbps actual download speed, so o2 clearly have a way to go but at least there trying. albeit after a lot of pushing.