Small White Butterfly

After the discovery of the 'Butterfly Lane' yesterday I cycled back there again this evening after tea for another session. The butterflies and the larger number of bees and bumblebees seemed to be more active tonight, i.e. harder to photograph.

However I persevered and I got this one. I've looked it up on the internet again and it's either a Large White or a Small White, it's not clear on the sizing. I thought it looked quite nice on the Rosebay Willowherb