So I ordered a second French one panel frame a few months ago from Robert/SD. As I recall, it was $150 shipped, 125cmx165cm, allowing 5cm extra both sides for breathing room beyond the standard 120cm x 160cm.
Not tough to rotate posters.
Find flat space, flip open, and remove:
New LB poster. Problem. Too big for frame.
Solution: Employ heavy-duty scissors to cut off half the excess linen all around poster:
Now fits:
Voila!
Bigger is better!