With regard to the last fix I noticed the the blade guide arm was skewed to the right with respect to the main frame and in fixing that I noticed today while cleaning the saw that the same arm was now not at right angles to the table but angled back a bit - hmm.

The blade guide arm which slides up and down for cutting height mates with that length of timber with the four screws. All of that had to come off to fix the skew issue and and when I fitted that bit of timber back I neglected to drive the screws back into the original holes. I lined up the top screw OK but failed to notice the timber was not parallel to the tension block (to the right a bit at the bottom) so the bottom screw ended up to the right of the original hole.