My wife ended up with a smart office attire, but the crowd was quite mixed - few in dresses, some in suits, some in jeans and some in shorts so short that I thought they turned up in their underpants for the wedding.

I turned up in a suit with a matching carnation (although funnily enough, no one else apart from the groom had a carnation)

The weather was fantastic and we had a great time.

Many thanks for all your suggestions!!