Not sure Peter Bellamy's really the best example of a Conservative or right-wing folksinger, for the simple reason that you could listen to and enjoy his complete recorded output and not necessarily draw any conclusions about his politics.

That statement is of course debatable: his fondness for Rudyard Kipling poems could be said to be a giveaway. But even that is hardly banner-carrying: it doesn't really bear comparison with the politics-within-one's-art holistic approach of a MacColl or Pete Seeger.

Moreover there are plenty of left-leaning singers who sing folk songs that, taken at literal face value, might be jingoistic, or celebrating things they don't themselves agree with (e.g. whaling or hunting or a victory in war or a famous general).

The only original Bellamy compositions I've heard are from The Transports, and if I had to compare them with anything I might mention Brecht/Weill in terms of subject matter (e.g. 'Abe Carman')