Aaargh. A day strapped int my corset so that I can keep trying this jacket on after each tweak…it had better be worth it.
I think [and several have commented] that there is a limit to how much I can fix, so it’s a good job I’m not a perfectionist!
 I have added a back stay, and reinforcement to the upper front of the jacket. I used an oddment of cotton corduroy, which was
[a] the right size
[b] a good weight
[c] to hand
I did this by just drawing a suitable-looking curve on the main pattern piece and cutting it out. I’ve basted it in for now, very roughly, as so much has to be undone again in any case. I will stitch it in more neatly when I do all the catch stitching of seam allowances.
 I re-stitched and pressed the left side seam, I think it looks better now, if not great.
 I’ve roughly pinned [for now] a little excess into one of the front darts, and slightly changed the overlap at CF.
 Finally, I’ve pinned a very small dart at each side of my bustline, to deal with that gap at the front armscye.
I think this will have to do.
I’m going to transfer the alterations to the lining and whizz that together, and make the changes to the darts.
Here are the pics at this stage, pre-sewing:
Will to live, currently zero.
Keep looking, keep advising, it’s much appreciated!