SW2012 SP1

I have a triangle base flange. Two of the edges have a 60 degree bend, the top edge 45 degree. Draws no problem with the 45 degree bend length linked to the vertex of one of the adjoining flanges.

Where it goes wrong is when I try to close the corners. I get a preview but an error saying 'Cannot find the other bends to close corner. Please make sure if the side faces of the two bends are connected...'

Anyone care to offer any thoughts or is this a metalwork step too far?