 macOS Sierra and the stalled Xcode update

For some strange reason, Xcode decided not to update on my macOS Sierra box this AM, instead just sitting there in a "Waiting" state.

As ever, I jumped onto Google and found this: -

Xcode update stuck at waiting

which says, in part: -

Copied from my answer in the developer forums:

Going to Applications in Finder and moving Xcode to the trash bin fixed the problem for me. As soon as I entered in my password to confirm moving Xcode to the trash, the App Store prompted me on whether or not I wanted to cancel the update or delete the app. I opted to delete Xcode, and the App Store immediately began downloading the update.

Once I did this, re-entered my Apple password within the Updates app, it just started working :-)