I’m just placing this topic here so that newer arrivals who may have found a way to do this can reply.
I know that the XA2 is not supposed to be re-lockable, according to Sony, but I have found their documentation somewhat lacking in places, especially as regards Fastboot drivers, so I am not ruling out that the possibility may exist in some way.
So, if someone does find a way to relock the bootloader on an XA2 then it would be good to get their attention, and ask them to tell us how they did it.
Hence this post…