The UK iPhone does support those being auctioned off by OFCOM but doesn't list them as so because non of those frequencies are being used at the time of it's launch.
Can you provide a source for this hopefully true statement - Apple would have no common sense reason not to list the supported bands and the 800 and 2600 bands are definitely not listed as supported.
Of course Apple doesn't have to conform to common sense either but there you go...