It is the one you saw
Rowdon The Burning (1981) - IMDb, Holly Hunter's in it too, it's a Friday the 13th clone but not bad as these things go.
I always thought it was the graphic nature of Tom Savini's special effects especially the raft attack which got this one into trouble. If I remember correctly [i can't lay my hands on my copy of See No Evil] they got a x-cert for it with cuts, but then it was sent out in it's original unedited form and that caused the master tape to be seized from, I think Thorn-EMI's offices and an obsenity charge brought which the company was cleared of. I'm sure
Scorpio will come along and explain it better than I.
Scorpio mentions Marc Morris [who I'm sure used to frequent these parts as well] and I bought the Video Nasties - Definite Guide DVD boxset that he produced which is a fine piece of work.