Update: I've re-(re-re-)calibrated the tone arm weight & it seems to play without a hitch, thank goodness - it even plays my copy of Martin Carthy's first LP, which it turns out is in really dreadful condition. No visible marks - visually I would have graded it near mint (and indeed probably did when I bought it) - but lots of noise. I've ripped it & edited out the worst of the scratches (which are highly audible even if they aren't visible!). I can only imagine that the original owner of this album really liked it and played it a whole lot, probably with a stylus that wasn't in the first flush of youth.