Confidence: It's likely to be this, but I can't be certain.
Notes: Matches other photos in I Spot and in British Moths and Butterflies - A photographic guide. Key identification features are the thin wavy white band about a third down the forewings underlined by black. A second white band nearing the outer edge makes a central arch which is quite distinctive. Also there are two black outlined irregular oval shapes near the edge of the forewings about three quarters down.