So here is the piece the was giving me problems. (rather a crappy representation of it for discussion purposes)
It is a flat PE piece that gets formed into a box but one panel of the box (red) has a concave surface. From MFH for FXX
I ended up dis assembling the PE to remove the part that needed bending and assembled the box minus this piece to start.
From there I really struggled putting the curve on the small piece without leaving a hard edge from my plyers. It would not budge trying to roll it around brass rod. It was suggested that I anneal the part to get it to bend easier.
Seems I should have left this one the parts tree.