Picked up the exhaust today from the fabricators today. He has removed the cat (downpipes and cat are all in one on the 2021 model) and remodelled the QD Y piece To fit the downpipes. The cat can also be replaced if needed. he's modelled it so as the airflow is all going the right way and overall made a great job. It now means the Y piece can be slid over the down pipes and fastened with exhaust clamps, the same goes for the cat.
As I say, he's made a great job and charged the princely sum of £140. CC engineering in Hull.