Yeah, it's just messing about above the water, so lots of traversing, jumping, sometimes swimming and stuff - we got really close up to seals and stuff too which was nice but then we wimped out of a particularly ominously looking bit of water with a gnarly looking whirlpool in it.
google turned up this history of coasteering
http://www.farmersmathry.com/page14.htmlOne of the better known routes is Magical Mystery Tour, HVS 5a, 7,700ft at Berry Head, and really the modern deep water soloing is the same thing taken in a different direction...up!