I need to give you guys an update.
I've just upgraded my hard drive on the laptop and I've found I had to change the dma settings. My settings now look like this:-
snd-cs4236 port=0x530 cport=0x210 mpu_port=0x330 fm_port=0x388 isapnp=0 dma1=0 dma2=1 irq=5
I don't know why this should be?
But it's working again.
Also I missed this detail from my original post, don't forget to save your alsamixer settings with the 'alsactl store' shell command when logged in as root.