The recipe I've got says to use streaky bacon instead of the belly pork (obviously the same thing, but cured), and remove the rind before cooking, so you don't get so much fat in it.  I reckon it would be best if you can get the bacon in the piece, but I'm sure thick rashers will be fine, if not authentic.  It also says to add a good tot of rum!

I remember cooking this years ago, and it was delicious, but had forgotten all about it - so thanks for the reminder; I may actually try this tomorrow, as I've got some portions of beans that I've pre-prepared and cooked in tubs in the freezer and I do have a really great local butcher (a Rick Stein Food Hero, no less).