Thanks, I'll give that a whirl.
You must check one of the tariffs to proceed to the next page (PAYG Classic is a good one to choose, same as 3's 3-2-1 these days), but final checkout page will only ask you to pay the advertised phone price, exclusive of any top-up charges. Then when the phone arrives, it will also come with a SIM card already set up for that tariff you chose but with zero balance on it. It's then entirely up to you whether you choose to top up that card (minimum £10 as you say), use any O2 or GiffGaff card you already have, or get the phone unlocked.
HTC Desire HD! That was a good afternoon coming home from phones4u, remember them?
How do you buy without a tariff? I can't seem to checkout without at least a £10 topup.
decent camera? :) but bad battery life? :( and not great screen? nice looking phone imho