Cardamine?

Cardamine?

Observation - Cardamine?. Description: This white flower with pale green leaves seems to resemble Large Bittercress (Cardamine amara) or Cuckooflower (C.pratensis) - but leaves me baffled.Can you advise? Growing on muddy edge of small woodland loch.

This white flower with pale green leaves seems to resemble Large Bittercress (Cardamine amara) or Cuckooflower (C.pratensis) - but leaves me baffled.Can you advise?
Growing on muddy edge of small woodland loch.