Two words: COOLING CLOTHS. It’s a special kind of towel that you wet, squeeze out and it stays cold for HOURS. I heard about them yesterday and got on Amazon and they arrived today. I’ve been using the same one for a few hours now and it’s still lovely and chilly, and I haven’t had to rewet it! I got these but there’s loads on Amazon. I highly recommend. We’re taking these with us when we go on holiday