Daughter managed to disable her iPad. Could get into recovery mode but unable to restore due to repeated network errors (code 3259) ended up multiple times getting part of the 1.66Gb downloaded then it froze and reset. Finally solved by manually downloading the ipsw file from iOS 8.4 repository then following the instructions here with the critical bit of info being to hold down the SHIFT key (windows8) when clicking the restore option to get the popup box to point iTunes to the downloaded ipsw file 🙂

The other top tip is to use firefox to download the ipsw file as if it freezes you can rt click pause and the resume and it doesn’t reset the download back to the beginning 🙂