Have a look here http://www.hendersons.co.uk/" onclick="window.open(this.href);return false;. However, if you only want a one off recucer or you're buyng just odd bits at a time, the postage may make them a bit more expensive than your local DIY store or plumbers' merchant.
You're right about the couple of bits I want for the QT, best to just buy locally - but the info will help when I start my proposed pond build, thank you.