I saw them at Broadstairs a few years back - I made a point of seeing them after hearing "Mad Tom's Song" on Mike Harding shortly before. If you're into electric folk then they're *very* good. I'm not sure I'd call it "heavy rock", but there's certainly a bit of goth or new-agey in there. It's a more synth-heavy and dancey kind of "electric folk" than you'd get from, say, the Levellers, but if you don't mind that then it's worth doing.