Hi Claire - sorry to hear this - always feel sorry for kids as I was lucky and didn't get it till adulthood - and its hard enough for an intelligent adult to face it let alone a kiddie.
Have you been recommended this book? Type 1 diabetes in children adolescents and young adults by Ragnar Hanas - it's written precisely for people in your position and actually is extremely useful for T1s of any age.
Not cheap but make sure you get the latest edition - it has sometimes been called '... teenagers ..' and gets revised every so often to bring it up to date again. My diabetes nurse at the hospital clinic always seemed to have it on her desk with Post-It notes stuck here there and everywhere with names on them, for things she needed to show patients! Rarely - it went back onto her bookshelf.
Are you also aware of the JDRF? - they organise all sorts of things involving children and also do research.
https://jdrf.org.uk/
Hope you get on OK - but always ask if you are ever in doubt or simply don't know something.