A wedding would fall under special occasions! The Queen adores weddings and would be delighted to open the garden to them for the event. If they don't have a wedding planner or an officiant, she would be happy to offer the services of one of her own. If they already have someone planning the wedding and officiating (or don't need one), she will make her staff available for their disposal to ensure that they have anything they need regarding decorations, food, music, alcohol, and anything else.