From back in the first half of the summer, what I now think is a chevron moth, Eulithis testata, (Lepidoptera: Geometridae). Initially I thought it might be a (somewhat faded) barred yellow moth, Cidaria fulvata, but a search through ukmoths.org led me to a better match with the chevron. The barred straw moth, Eulithis pyraliata, also looks similar, but holds its wings in a completely different way when at rest. The colour of chevron moths apparently varies from a light yellow as above, to a quite dark brown as shown here at Scarborough Wildlife.
Photo taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2009-06-21.