Thanks chaps....
I am very very chuffed with the results, particularly as I did it all myself
The HU is a JVC KW-AVX840, I wanted a 7" screen to fill the double din, didn't need satnav and the JVC fitted the bill
So far so good, although it has locked up a couple of times playing my iPod classic, but that may be because I am using the iPod cable from my pioneer....
The sub is a LOT bigger than I thought it would be, I knew I should have looked at the dimensions
The sound quality is great, nice deep rich bass and surprisingly rounded considering its a flat sub... no doubt at all that a sub or pair of subs with a box would sound better but it would have taken some fabrication and would have cost a fair bit more than the £250 for the Pioneer, especially as it is active which saved on getting a separate amp.
It was really easy to fit, just a permanent live from the battery and then a remote and an RCA to the HU, also it has a nice remote control which is now in my cubby, and NO Jim it has not been above about 40%
I need to sit and get everything set up nicely, another good thing about the JVC is that you can tweak lots and lots of features of the output
The CF is an RSW kit