Teen daughter leaving for Europe in 48 Hours? What am I forgetting?

My daughters High School choir is leaving for the UK and Ireland for a 10 day trip. I have never travelled to Europe. If you have travelled there, please advise me of anything you won't find in a brochure! "Must haves", "Should Haves", "Wish I Would Haves"....etc. Any and all advice appreciated as I am pulling my hair out!! She has Pounds, Euros, cash, plastic, European Chargers, Pport, European cell phone, but my gut tells me I am forgetting some simple stuff that only experience would tell you. HELP!!! Aaaaaahhhhhhh.....