I took the exhaust into GD today. What I initially thought were that the cat pipes were short, but it turned out that the centre bobbin support bracket was in the wrong place. It would appear that there is a slight difference in the placing of the T56 5 speed gearbox mount and mine which is a 6 speed. Lester whisked it away, a quick flip over of the support bracket and 10 minutes later he had it all sorted. Customer service at its best.
No excuse now, just need to fit it.