I suspect this is an unusual hybrid between the Early Spider Orchid and the Bee Orchid. It didn’t appear to have any of the vigour typically associated with hybrids however on the thin soil on top of the sea cliffs the majority of plants appear stunted.
Early Spider Orchid, just coming to the end of its flowering season. Fortunately these two had escaped the attention of the cattle.
The bottom 2 photos are more typical of the normal Bee Orchid.
With the flowering season of the Early Spider and Bee Orchid overlapping and both species being in the same family hybridisation is likely to have occurred.
With a large group of Green-winged Orchids close by there’s a chance of this plant also being a hybrid. It actually looks too white to be a simple white version of the Common Spotted Orchid. It was also significantly larger than all the other Spotted Orchids.