Mirrored parts oddity

I'm modelling a facia in sheet metal parts for a double sided product. I've designed it so the parts work on either side of the unit with the exception of one, an end panel. due to the design this is the only part I can't use on either side and requires being handed. Now, in a normal sheet metal shop I'd just as for one as drawn and one opposite hand but the company I work for seriously frown on such things and insist on a separate part/drawing. Their choice, I work to their rules, they pay the wages.

So I originally created a mirrored part, independent of it's original, saved under another part number, inserted it into my assembly, great, perfect, happy bunny. Then it came time to create drawings for these panels, as I inserted it into the drawing I spotted it was the wrong hand so opened the part, that too is the wrong hand (it's exactly the same as the original part it was taken from), what the..... Open the assembly, all is exactly as it should be, reopened the part from the model, wrong hand????? Anyone any idea what the hell me/solidworks has done wrong?

Unfortunately I cannot supply the parts and assemblies as they're quite sensitive in nature and for a government project but I have attached a couple of screen shots showing what I mean..

SolidworksModeling And Assemblies