changing uuid of mdadm array

[Tim Woodall <debianuser@woodall.me.uk>]

I wanted to change the uuid on a component of a md raid1 array.

I found the following worked and didn't delete any data:
mdadm --create /dev/md1 --level=raid1 --force --raid-devices=1 /dev/sdb3

but I couldn't find any way to change the uuid in the member without
creating the array like this.

This didn't work
mdadm --assemble --update=uuid /dev/md/1
Started the array but didn't change the uuid

This doesn't work at all
mdadm --assemble --update=uuid /dev/sdb3

Is there a good way to do this without starting the array?