Nop, do NOT get that PSU from the link up above.
For the 6800GT, you need a PSU which is what is called.... > ATX 2.0.
This high end graphics card NEEDS a psu with 2.0.
I have a Tagan 380W.
I have the Leadtek 6800GT, DFI Lanparty ultra SLI-DR blah blah blah, the best, and most expensive out atm.
And guess what, i also have the 3200 like you.
I did the psu calculator, and it said I was using about 318W or so.
Obviously, because I have the 380, it should be fine ,( not for overclocking though..)
Mr DJChris is mr braniac at al comp stuff, as are pretty much most of the high end posters on this forum. Im sure they will get back to you about this.
Btw, I also live in UK like you, and just built my pc about a week ago.
UK Sucks for this kinda stuff, not like newegg.com where you have about 200 more items to choose from, for each item you are looking for.
The Tagan 380W which i bought is at overclockers.co.uk. It is a good PSU for 44 pounds, inc tax.
I would recommend this..
Its pretty much cheap for Britain, and good quality..