Udea olivalis.
(Udea olivalis)

Easy to recognise but, as it has no English name - only a Latin one, it is difficult to remember.

Information:
Shades of grey/brown all over except for a prominent but fuzzy white square and several equally fuzzy white spots on each fore-wing. This is its typical resting stance.
Fore-wing length: 10-12mm. They fly June-July and can be seen over waste ground, gardens and woodlands.