Pretty sure there is nothing useful nearer than Mendip Chris, but if you are travelling down from Oop Norf (ish) then is there somewhere "on the way" perhaps, although You may have to detour even then.
As Darren says though, what about some builders hats and cheap lights? Probably do that for almost the same price as hiring, although the quality (and quantity) of light might not be too good.
Perhaps asking on Darkplaces might be worthwhile too, you never know.