The (joint) biggest discount is being offered on the base Surface Pro 2 with 64GB of storage, which has been reduced by £150 to £569. Of course, you'll still need to buy a Touch Cover (or Type Cover) to get the full productivity benefit of Surface, which will set you back a further £100 (or £110 for the Type Cover).
The Surface Pro 2 128GB model has been reduced to £659 (a saving of £140), with the 256GB machine down to £899 (again, a reduction of £140). Finally, the Surface Pro 2 512GB is now £1289, which is £150 off (but still eye-wateringly expensive).
So the upshot is you can now get yourself a Pro 2 for £569 – though you might want to compare that to the Pro 3. The new model is coming in with an entry-level price of £639, and of course for that extra £70, you're getting a 12in screen (boasting a higher resolution, and a 3:2 aspect ratio), and of course the benefit of the new design which is much thinner, lighter, and boasts an improved kickstand. For more details and comparison between the two models, see our Surface Pro 2 versus Surface Pro 3 spec comparison.
We'd be inclined to hang on for the Surface Pro 3 if you can possibly wait – or indeed hang on for potential further reductions in the Pro 2 as the summer rolls on.