Hi have you tried Deeside Service Centre (01244 535 534),based near Chester,they make bespoke exhausts and have made about 6/7 for me over the years for customers,They range from £250 -£1000 depending on what you want.
They will need to see your car but it is worth it,they are stainless exhaust systems and carry a lifetime garuntee,and you can have it as quiet or as loud as you like and have options on your rear exit tailpipe,so its exactly like you wanted.