Eucosma cana, also called the Hoary Bell, is a tortrix moth that lays eggs on thistles and knapweeds (as above, on knapweed at midday).
Wingspan 15-23mm; UK flight time Jun-Aug, from early afternoon into the night.
Dichrorampha vancouverana
Summer day-flying and evening moth thought to be vancouverana. Wingspan 12-15mm; UK flight time Jun-Jul.