"I doubt many exponents of early music reckon they're continuing an unbroken line of madrigal singer or wotever."

Sure. Indeed in my (admittedly limited) experience folkies are wont to bandy around references to 'the tradition' and 'the folk process' quite freely, while referring to revival songs and tunes rather than traditional material. That hardly concerns me, but it is curious that the ideas have been embraced (in a fashion) while the music itself yet remains other. If I felt I could get away with singing Dowland at my local singaround I happily would, but I fear I'm pushing it with unaccompanied ballads as it is.