Thanks for the heads up Brians256. I've searched for BillA's posts and also for D4 serial, but no joy (well, no joy in the fact I've found nothing, which I suppose could be good?

)
Satanicoo - I'm certain 1 x D4 will be enough, but if 2 D4's provide 17 ft of head, which they should, then (referencing Cathar's article about head / flow / C'/W) 2 x D4's should provide a 1'C drop on the CPU temp, which I'm willing to pay £50 extra for.
Re: Storm. I've heard about these, but cannot find them in the UK. I can find the NexXxos blocks though and I've heard mixed things. I've used the LRWW before, and apart from cracking the lucite

I was very happy with it!

I'll get brass-topped blocks this time round...