Have managed to follow all the steps in the process, and have an unlocked phone which I have set to three with updating the settings - joy! But, no WIFI.
I have the QCN file from running the backup part of the process, and followed the restore steps, but it's not restored the Mac address. No, I didn't write it down. :(
Would anyone have a backup to share or thoughts on ways around this? I've tried the qcn file very kindly provided - DEADD00D_23.qcn, but no joy.
UPDATE: rebooted again today, and now have a mac address - hurrah. It all works fine then. Thanks for all the guides posted here.