Thanks for the replies and input everyone.
Why am I not using peat? I want to try something else. Neopeat for example is very easy for me to get hold of. There's also the environmental impact issues of using peat, that I don't want to get into an argument about. Basically I just want to try something else.
Thanks for mentioning Tim Bailey - he seems to be having success with coir.
I've used nasty acids when I've done lab work before, so I will take suitable care if I use any.
Sphagnum, pine needles and humic acids are all good suggestions thanks, I'll try some things out and see what happens...