Thanks for the tips David! Lemon oil was the first thing I applied to the fretboard after the strings came off, but polishing the frets sounds like a great idea. I don’t have any steel wool around, but I’ll see if Flitz is up for the job. This also gives me a chance to have a closer look at the B natural octave on the G string, which sometimes craps out and sounds a C.
Cheers, Oliver