Butterfly

Today we caught up with lots of jobs in town - library, hair cut for Theo, tea and cake, buying pumpkins, among other more boring tasks. Once home we played a little in the garden and found this butterfly. It slowly walked across the grass to us (I hope it was okay as it didn't attempt to fly at any stage - Theo was very concerned for its welfare and wanted to check on it again before bed!).
Please feel free to educate me on what type of butterfly this is. I could look it up but haven't achieved that yet!