Look who's peeping through my kitchen window

Friends came for dinner this evening and as they left I remembered I didn't have a blip then I noticed this moth peeping through the kitchen window as I washed up. It very obligingly stayed there for a long time as I tried a variety of ways to get the shot without getting me in the reflection in the window. I don't know anything about moths but looking through my book I think it may be a Brimstone moth but I'm happy to be corrected. It says in the book they are a common visitor to lighted windows.