Can't remove wrong email address for iCloud - please help

Hi all. I have been scouring and reading various ways to reset this iPads iCloud Account email address.

The problem I have is the email address was entered incorrectly as it was set-up, for example myname@netpace.net.au instead of myname@netspace.net.au

I am able to login to the ipad, itunes etc with the correct apple ID etc using the netspace one, but I can't remove or replace the iCloud email address and it keeps asking for the password to the wrong email address (netpace). Unfortunately the owner has no idea what the password is or was for the wrong netpace account, we have tried everything they had written down or remembered but it will just not accept any of them. We can't recover the password as the netpace.net.au email address does not exist.

The owner is happy for me to do a full restore to factory reset but it will not allow me to as Find My Phone is on and I can't turn it off, even via iCloud.com as the netpace email address is incorrect. Obviously I can;t access iCloud.com with the netpace wrong address, but I can login with the netspace email address. The find my phone shows no devices on the correct netspace.net.au account used to access iCloud.com, the netpace (wrong email address) will not log in with any of the passwords they have written down or can remember.

Can someone please guide me on how I can sort this out please,

Thanks

GW