Contact BCS direct or you could try you'r local tyre/exhaust place?.
Thanks :D
I had contacted BCS who were more than helpful.
For people who come across this, the powerflow exhaust is not recommended for fitting as a catback system (BCS only supply it as part of a turboback system) as the sound reduction from the standard downpipe restricts the sound produced from the powervalve therefore rendering it almost pointless.
I have been told that installing this exhaust as a cat back system will not damage the exhaust or car and requires a reducer pipe which BCS are going to supply for me.
I will thereafter have to cut my standard system after the cat and install from there should be straight forward (hopefully) lol.