Yeah took all those points into consideration along the way and it was simpler overall to go with the new sheeting.
As expected I have been distracted with any amount of side issues elsewhere but have managed to single-handedly cajole the lower section into (sort of) the right position on the driver's side.

So ignoring the minimal number of clamps and tek screws holding everything in place, this should make clearer what I have been trying to achieve. There are still some little tricks I won't mention at this time to take away that slab sided appearance . . . but that will come later. Also try to see past the waviness of the sheeting in places, it is a work in progress after all.
And the little bit I had been dreading, where the sheet was split so the top would curve around, but the bottom did a sharper bend set back slightly from the curved bit. An unnecessary complication, but it is how I have envisaged this from the start (for whatever reason!?) - basically the step will be extended back further than standard to assist access into that kinda cramped door opening.
Not 100% correct, but within
MY acceptable tolerances.

Note, creating the curve was no drama, but the right angles were a little more work - particularly towards the centreline and around the frame upright.
The most frustrating part about this is the fact it will all need to come back off (probably several times) before final fitment AND the other side has to be done next. On the positive side though, the strip above will be a doddle in comparison.