I don't think it is unusual for the roll bars and cages to be a bit of a sod to fit, stories of people using ratchet straps to help get things to line up and needing to elongate holes spring to mind. Not trying to excuse it, but it is an area where I remember others having difficulties and tackling in different ways. My Academy roll cage was a real PITA to fit, took a couple of evenings before I had all bolts fitted.