White bluebells?

I'm not sure if these are actually white bluebells (which Prof. Google says do exist in the UK, but are fairly rare), or one of the flowers that look very similar. They were in a patch of 'normal' bluebells, and seemed to be identical in size, stem configuration, etc., although they were in full bloom and the normal bluebells were fading past their best. I'll not identify exactly where they are, but say they are on the East Neuk of Fife (they may be common in that area for various reasons of microclimate, soil conditions, or whatever).