Track days always fix my squealing. I have lost my rear shims though. I tried putting two thicknesses of aluminium can in there instead but that didn't work.
My rears have been squealing for ages now but I've had no track days for ages either. Tomorrow I will pull the pads out, lightly sand them to deglaze them, then put them back in and bed them good and proper. Sunday I'm going to the track.
I will report back on monday.