Hen party dressing covers a genuinely enormous range of occasions depending on who is getting married and what has been planned. A spa weekend in the Cotswolds requires a completely different wardrobe to a long weekend in Ibiza, which is nothing like a dinner in Mayfair, which bears no resemblance to whatever is happening in a bottomless brunch in Manchester on a Saturday afternoon. The one consistent requirement is that you look like you are celebrating and that you have made an effort proportional to the occasion. The thing to avoid at all costs is showing up underdressed relative to the rest of the group because that energy never quite recovers.