Viola or Violet

My dear friend MrsToad was kind enough to tag along with me today and helped me unload plants for the local NSPCC Plant Sale.

As a little treat we went for a walk at the Newborough Warren and Llanddwyn Island National Nature Reserve where I blipped this gorgeous like group of flowers clinging to a sand dune.

I have failed in my attempts to identify them so if anyone knows what they are, all suggestions will be welcome.