This is Anacamptis laxiflora, the loose-flowered orchid. Its not found on mainland Britain at all so this is the first time I've seen it. I really rather like it. Like a lot of European orchids this one likes damp, unimproved grassland and it seems to be present in good numbers.
In addition to the flowers not being as tightly held as the Dactylorhiza species I've noticed that this one seems to grow in a slightly more scattered way than the Dactylorhiza which, when present seem to often form relatively dense patches. I wonder if this is an optical illusion caused by the more delicate flowers. 1 down, 3 to go. Enjoy.