Hia. A letter from your GP detailing your condition and medication is usually all you need. Many of us on this site use the Frio cool wallets to store our insulin when it's hot and/or whilst abroad. So, when I used pens (now have a pump) I would carry the pens And spare cartridges in these Frio wallets. Once I'd reached my holiday place I'd store my spare insulin in the fridge in the room and just keep my injecting pens with me but in the frio. They are a bit expensive but are brilliant and last ages. All you do is take them out their inside pouch and soak them in cold water. The crystals inside then activate and they keep things cool for ages. Just google them - I know that amazon sell them but also your local chemist do as well. Hope this helps.