How DID I sew before the Internet?

'Toteworthy' nailed it...the problem with the jacket wasn't the mysterious unknown alterations, it was that I put the collar on upside down!!

Spent a bit of time spent unpicking and resewing and...TA DA...the humongeos error has evaporated:

It's wrangled and mangled and in need of a good pressing, but I am back to the point I was at last night.  And the collar is as it should be.  A long shot from perfect, due to the fudging necessary to deal with the already-trimmed seams, but WAY better than it was.

Obviously, the guide sheet is a necessary friend for this project.  And, since I recollected that page one/two of the guide sheet was missing from the envelope when I originally cut the jacket out, I signed up for Club BMV and ordered another copy of the pattern.  

I'm going to have to make this again, correct from the beginning, and see how it turns out. ;-)

Thanks to all my internet buddies who offered consolation and advice, and especially to 'Toteworthy' for spotting the actual error!!