OK, so I'm pretty sure the answer is "replace the whole panel with a Heritage one", but I need you guys to help me bite the bullet and make that decision.
Issue is that also the scuttle panel is in solid condition (not a sign of rot anywhere) I'm sure a previous repair was done without due care and attention. The left hand end of the scuttle seems to be 1/4" proud of where it should be (i.e. that side of the car is 1/4 too wide if you get what I mean). Not too noticeable until you look at the seam that runs down that corner of the car beside the windshield (i.e. under the seam cover). Instead of the panels being flush either side of that seam, the one to the front of it it good down to about 4" above the scuttle then kinks out 1/4". To correct that the scuttle needs either a new end panel fitted (and lots of fettling!), or rip out the whole scuttle and fit a full Heritage one.
On the plus side I'm in the process of stripping the whole car down to bare metal for a respray (i.e. windshield etc is coming out anyway), and it's a steel flip front so no worries about messing with wings etc.
In my position what would you do... spend a good few hours curing and swearing while trying to get a Magnum repair panel to look good, or bite the bullet and fit a full Heritage scuttle?