Just to let you all know that Tesco currently have the Cadbury's Medium Selection boxes (6 bars) Buy 1 Get 1 Free - they are £3 each (which I think it about 21p dearer than Sainsbury's deal, but I know not everyone has a Sainsbury's handy). They are also Half Price in Morrisons (slighty cheaper by about 20p but again, Morrisons aren't everywhere - and if you're going to Tesco anyway it's not much of a difference).
They also have the Nestle version with 6 bars, Half Price from £3.00 to £1.50. This selection box contains: JELLY TOTS Bag; MILKYBAR Small; TOOTY FROOTIES Bag; MILKYBAR BUTTONS Bag and 2 x SMARTIES Tubes. These are more expensive elsewhere - the offer is 2 for £4 at Sainsbury's on these.
Hopefully this may help somebody.