Hi Per - I used Bend on the original plate from the top view - Use Project on the Osnaps here to keep things in plane. Set the start of the bend axis on the mid point of the edge or the Quad of the arc in top. Set Symmetrical=Yes. Snap the end of the bend axis to the quad of the arc at the end of the plate. Snap the final bend to the end point of the curved surface’s arc edge. OffsetSrf the result, ExtractSrf the outer face (or use Solid=No on the OffsetSrf) and UnrollSrf.
Watch out: The round holes are distorted by this process - you may want to mark the centers with points and remove the holes, bend the points with the plate,
Pull the bent points to the offset plate, unroll the points with the surface and then use the unrolled points to pop some holes of the correct size. Not sure what you need in the end, but just in case. HolePlate_PG2.3dm (282.9 KB)