At the end of the day, Harrods is a shop. You are a customer. They want you to feel welcome. But you also want to feel like you belong in that magical, over-the-top world. Wear something that makes you smile when you see your reflection in a gilded mirror.
I once saw a family in matching silly Christmas jumpers during December. They were laughing, taking photos, and buying toys. They didn’t look “posh,” but they looked joyful. And that is the best accessory of all. So pack your best “day out” outfit, leave the muddy wellies at home, and enjoy the glittering madness.