Taking DSs who are 12 & 8 for a trip to Buckingham Palace followed by tea at the Goring. Weather looks like it could be hot so now wondering what they should wear. Want them to be comfortable for walking around but smart enough for the afternoon tea. Wondering if you think they could get away with a short sleeve shirt on a hot day or if it really should be long sleeve? Have ordered some loafers to go with chinos for both of them. Could bring long sleeve shirt in a backpack but then risk they could be crumpled. Anyone been before? How smart is everyone dressed?