I've found numerous posts that allude to being to replay individual completed missions, even one noting that replaying them before completing the campaign might uncover a bug.

I've a simple question (and no doubt a simple mind as I can't sort this out): By what method is this achieved? I have yet to find a mechanism to replay a mission once it has been completed.

you can pick and play any mission prior to the one you have most recently completed from the campaign screen use left d-pad or left arrow button on yer keyboard to see prior missions...

Well that was intuitive and obscure at the same time, silly game developers. Thanks! I appreciate the help.

yeah K you the man.....