Update: (I can't believe it's over a month since I looked at this..
Today I got the latest LXDE CD and vowed to put this right or bust.
I was getting alot of irq conflict messages during boot. In the terminal this message barges in rudely: "Disabling IRQ #16".
So in dmesg, I found this: "Disabling IRQ #16 nobody cared (try booting with the "irqpoll" option". Ah!
So I added "irqpoll" to my grub line now all is good with the world.
I have removed the sata add-on card and it looks like I can get on with configuring this one for it's intended owner. I promised him "ready before Christmas", however I didn't specify which Christmas...