I'm looking to do a UK based ironman in 2017. My weak point is the swim so a river or lake swim rather than a sea swim. I know they can be expensive, but £400 or £500 is a bit beyond me, looking around £250 mark.
If youre looking to do an "ironman" then you haven't got much choice and will have to fork out nearly £500! Less expensive is something like the nottingham outlaw, which is the same distance, but cheaper at around £300.
If you are after something that's unique, and completely different check out XMAN XXX Wimbleball. Lake swim - Very lumpy, bike! - Epic trail marathon.
£160 - great value but most of all a real challenge just to make the finish line in under 17 hours check it out here: http://xmanevents.com/xman-wimbleball/ with hay bails, cider, and bbq waiting at the finish line. No Frills and lots of thrills!