Stewart Robert Hinsley writes
Once you've learned to recognise a plant it becomes often becomes
surprisingly common. I never knowingly saw native Dactylorhiza, except
for a colony in an NT garden, until last year, but I now know of over a
dozen localities.

It can be in hordes - hundreds of flowers in an area. According to
Harrap Orchids of Britain and Ireland "In much of Britain and Ireland
this is the commonest orchid, and it is often to be found in large
numbers. Nevertheless, there are large tracts of countryside that are
not graced by its presence".

It seems to be commoner than other orchids; I haven't seen any others
growing wild.

You have to be in the right bit of the country :-) (Limestone helps, as
does absence of sheep) On Monday, when I was caving not botanising,
there were a couple of dozen common spotted next to where I parked the
car, with 3 or 4 twayblades. A couple of weeks ago, an afternoon's
gentle ramble netted early purple, common spotted, northern marsh,
twayblade, frog, fragrant, and bee. Next time I am confident that I will
see another 3, possibly 4 species.

--
Kay