I went to a Martin Simpson workshop several years ago, and on a break between sessions, he talked to me a bit about Martin Carthy's technique-
one thing MS told me about MC that was utterly critical to me in learning Martin Carthy's stuff is to remember to keep your alternating bass drone- strict tempo! There are a variety of tunings that work well for Martin's tunes. My favorites are
CGCGCE
CGCGCD
or variations on these, tuned
half a step up or down to fit other keys.
DADGAD and DADCAC work nicely too!
Open "C" (CGCGCE) is a great place to start, because it clearly states
a key- and by retuning the high "E" string, either a half or a whole
step flat you can get into "Cminor" and "Csus4" (the C version of DADGAD)
Have fun!