I'm with Jim on this, but must admit to owning the early stuff + the extended double disk Castle edition of Lark in the Morning with the radio sessions which reveals a rougher edge, though quite so rough as Mr Fox who at least provided an alternative to the Steeleye / Albion / Fairport axis (aka The Hutchings Dynasty) with respect of English Folk Rock which never quite got up to the same sort speeds reached in France with Malicorne etc. Still, there is a charm here that pervades to this day. Of course you'll have all seen this:

http://www.youtube.com/watch?v=HGHYl7Kv50g

Which was recorded in 1970, when I myself was either 8 or 9; I recall it from school, along with so much other folky fol-de-rol which I either found irksome or inspirational, but which never lived up to the promise realised on Bright Phoebus and The Battle of the Field which turned out to be swan-songs, pretty much.

My friend Ron Baxter maintains that Steeleye Span didn't do Folk Rock as such, rather they did Folk with Electric Instruments; I'd say that's about right, although I still wake up screaming when 700 Elves invade my nightmares....