OK, some additional eBay-fu reveals that if you're willing to buy a larger system (1.5kW to 5kW), it's a bit cheaper than buying individual panels...
So, for a 5kW system, consisting of 15x330W panels, one inverter, no mounting hardware (that's separate apparently), but you get a pile of MC4 connectors worth pennies... you'll shell out a mere £3,295. And you have to go pick it up, they won't ship it, so factor in another £150 to hire a van & fuel it.
Anyway, that base price in US & AU dollars, for shits & giggles: US$4580. AU$6853.
Not to mention the fact that solar in the UK is crap compared to much of the US and virtually all of Australia... The sunniest place in the UK (the "delightful" Bognor Regis) gets 1902.9 hours of sunlight per year (apparently). No idea what that translates to in power terms though, considering that for much of the year our sunlight arrives at such a shallow angle it expends most of its energy just getting all the way through the atmosphere to here...