Seems a good price for the three series set.
Even though it's a pre-order and not out until march 16th, with Amazon's price promise, if you pre-order now they will honour the price when it is released.
With series 1 and 2 going for £14.65 on their own, and series 3 going for £12.98 paying a couple of quid extra for all three seems good value!!!
Shame its such a long wait, although we are only on episode 2 of series 3 now!