Dog Violet ?

Entry 400!!! wow! time is flying!
It has been a busy day today. I spent the morning doing some crafty things with two lovely friends, followed by a good catch up with another friend ( who I have known for over 40 years) at lunch time. I loved all the different chat, and managed to learn some new crafty skills which was wonderful!
Consequently I was yet again nearly blipless! I decided to drive home from the village of Rusper via Wimland Hill where I stopped off to take a few shots of the wild flowers growing in the verges there.
Last year, the violets growing in this verge near the top of the hill had a broad white stripe in the middle of the lower lip petal. They were all like it, not just one plant. This year every plant has flowers which are mainly white, mottled with the usual pale purple violet colouration - all very odd!!
I wonder if anyone had any ideas? there were no other violets of any other colour close by. I think they are Common Dog violets Viola riviniana, but I could be wrong as my ability to id all the different types is quite limited - I am willing to learn though!
On my way home I got stuck behind an old fashioned steam roller steaming down the country lane.....was an interesting sight.