Just had a email through from giffgaff saying they are increasing my data in the £12 bundle to 3gb and just looked and it seems like they've made a few more changes to other goody bags.
£5 bundle - extra 25 mins
£7.50 bundle - extra 250mb
£10 bundle - extra 1gb or 400 mins
£12 bundle(s) - extra 250 mins & extra 1gb data
£15 bundle - extra 1gb
These deals aren't active until the 22nd February.