Spirits of Salts is another one to look out for, that's HCl...I found a 5l bottle going on Ebay(.co.uk)
Isn't NaOH sold in pure, cystalline form as caustic soda which can be bought from any supermarket?
I also found a guy selling Liquid mercury at £10 / 4oz Plus postage which suprised me because it's apparently hard to get hold of. I didn't buy any though, I don't want to touch that stuff...
Someone else was selling 2l bottles of battery acid from a garage clearout although he wouldn't post them
I found a site called http://www.reagent.co.uk/ which seems to sell everything although I assume it will require a license number of some sort at some stage during checkout for the controlled chemicals.
Pottasium / Sodium nitrates, and Pottasium Permanganate and other such oxidisers can often be bought from ebay.co.uk too
Hell, most chemicals can be got by someone with enough experience / money / determination!
Paranoia is hitting me now because I'm sure everything I have said is just far too obvious, but oh well.