Cat exhaust and IVA

When i first ordered my kit, and having a bit of a discussion with the guys up at westfield, i was told that a CAT would not be need to be fitted to the car, Simon pointed out a loop hole in the regulations, that would mean if i was to get a letter from Mazda saying that the engine was manufactured before a ceretain date, i could pass the emissions test with no problems without a CAT. Well after a bit more digging into the IVA manual it turns out that you are no longer able to do this, and that all cars manufactured after 1992, if they were originally fitted with a CAT then it would need one regardless of the year of manufacture, this means that i have had to order a CAT exhaust from westfield.