They look really spectacular and what is significant is that a field on the other side of the little lane, so it is literally 5 yards away has no orchids. This most likely indicates some difference in the way the two fields have been managed in the past. I suspect the orchid field has been managed in the same way for hundreds of years. The photo below is another part of the same field.
That’s it. Well almost, there is a brilliant web site where you can check out different flowers and fungi and animals but here is a link to it which will take you to Marsh orchids and then you can decide for yourself which ones these are..