While was very impressed by the stamina, strength, and will power of those doing the DW did have a serious concern about some of their lights, or rather lack of.
Last night the stragglers of the "overnighters" came down the Thames that I saw had just illumination in the direction of travel, i.e. downriver, typically in the form of a head mounted white light.
None of those I saw had any lights at all upriver. Once they had gone passed it was very hard to spot them, a shadow against the reflections of street lights.
This is potentially very dangerous as the Thames in the tidal area does have traffic, and some of it can move very quickly. As these DW overnighters went under Putney Bridge there was some form of incident (probably and rather sadly someone thinking of jumping off that bridge) and so a Police launch went up river at roughly 30 knots while the RNLB lifeboat came down river at presumably equally fast (though couldn't see it) joined later by a more sedate PLA harbour master's boat, swinging its spot light from side to side, just in case.
So thats three boats that can go fast enough and are hard & big enough to do a kayaker some serious damage. All craft have a duty to show sufficient light for other craft to be aware of their presence, but these kayakers most definitely did not.
I hope they were ok but seriously as it would cost a only few pounds its not just thoughtless but dangerous to not buy that second head light.