Thanks, Mark.

Tried this, same problem. No change at all...

Edit: I think I might have found the problem with it trying to create both as md0. I booted from a USB stick and ran 'mdadm --examine --scan --verbose' and it came up with two arrays, which is correct, but they both showed up as /dev/md0. The rest was correct. How can I rename one of them to /dev/md1?

Edit2: I tried 'mdadm --assemble /dev/md1 /dev/sdb2 /dev/sda3', stopped it and it was still showing as md0.

Stig