This thread has been great! I've started planning for this today and can't help but feel I've forgotten something. 
I've got the uniform, shoes, last year's coat (in case of snow). Need trainers.
DD will use last year's school bag until half term (her birthday) and then she'll have a better idea what she wants.
She got a calculator as a leaving present from primary school. Has a pencil case, protractor and set square set, colouring pencils/ pens. Need writing pens.
Will get the Really Useful box with foolscap suspension files for keeping her books in. Plus A4 wallets for each subject if required for loose items.
Will print out copies of her timetable and put them everywhere; one of the lid of her box, one by her bedroom door, one in the kitchen.
Checked out the bus timetable and registered for mobile tickets so she can buy them via text message. No need for emergency taxi money as DH teaches at the same school.
Can't put money on her canteen account yet as we haven't got the login details. But she'll be taking sandwiches anyway.
Will set up a good folder system on the PC for homework.
Hopefully that's everything for now. I feel like I'm preparing for an apocalypse, there's such a sense of trepidation! DD is fine of course, but that's because she has little understanding of how organised she needs to be and that she has to be ready 30 mins earlier in the morning.