True blue?

Found this pimpernel in the new chalk scrapes we have dug out to create improved butterfly habitat at my nature reserve. There is a blue form of the very common Scarlet Pimpernel, but it's just possible that this is the true Blue Pimpernel Anagallis arvensis ssp. foemina, a very scarce plant of arable field margins on the chalk. Of course, once I got home and checked it out I realised I should have picked a leaf so I could check the tiny hairs under a microscope. All the other features look good for the subspecies, but I can't say for sure until I visit the site again.