Stick with what you're wearing! If there's anything I've realised over the past couple of days (you're in bristol too, yes?), it's that sunny weather means you can get away with so much more casual outfitts, but still looked refined compared to everyone else.
Suits will look very stuffy outside in nice weather, with the possible exception of a navy one with penny loafers. The outfit sounds tidy and you'll stand out, for all the right reasons.