Finally fixed it! You have to downgrade to 8.4.1. Outlined the steps below.
Step 1 - Backup your pictures! Even though you can't get to your phone and use it you should still be able to backup your pictures
Step 2 - Download IOS 8.4.1 for your iPhone or iPad from this site --> https://ipsw.me/8.4.1
The file was taking a while to download for my phone so I searched the filename on Google and downloaded from Mega.
Step 3 - Reboot phone into DFU mode - hold down power button and home button - when it reboots let go of power button - still hold home button
At this point it will ask you to connect your phone to iTunes - will have to connect phone to the computer.
Step 4 - Hold down the Option (Mac) or Shift (Windows) and and then click restore.
Step 5 - Browse to the 8.4.1 file you downloaded and select it. This should restore to the previous IOS version. Note: This will wipe phone.
Step 6 - Restore from backup. Hope that you backed up before attempting to update.