Yeah, those three narrow strips of thin brass really are the Achilles heel of these lanterns. Once the lantern falls on its head and they get creased they're badly weakened and need some sort of re-inforcement. Looks like you've done a good job, though... Regarding the IF 54 'pig-heater', you can get a decent match of blue paint in a rattle-can from Halfords - the exact name of the colour escapes me at the moment - it was a few years ago...
Re David and IF54 colour. Ral 5002 Ultramarine blue seems to be the current farmer palmer blue. I have tried a sample and it seems close enough.