@MichaelMulvaney thanks. It's a dusky-blue, but without an underside image I can't pin it to species; both species fly early in the season. @DavidDedenczuk it's a lovely fresh individual! Did you manage to get any underwing shots at all?
@SuziBond @MichaelMulvaney Hi folks. Sadly the butterflies were fully opening their wings as soon as they settled. I was hoping for an underwing photo opportunity, but didn't get one. I've added another photo of another individual nearby.