Desktop contains entire home directory after drive replacement

[brian]

This is a weird one. The drive containing my home directory was giving
errors, so I replaced the drive and copied over the entire /home tree
onto the new drive, then switched the mount points in /etc/fstab.

When I rebooted with the new configuration, suddenly my desktop (XFCE
4.12, Ubuntu 16.04 64-bit) contains EVERY file and directory in my
home directory (and there are a lot of them!). I have searched in vain
for a logical pointing at the wrong place, the contents of my Desktop
folder are exactly as expected, I simply cannot think of what went
wrong during what should have been a routine drive replacement.

Does anybody have any ideas, please?

Brian.