Squeel on start-up

[Steve Tinker]

Apart from the belt slipping (which it shouldn't as the tensioner should be - er - tensioning), the rollers usually get noisy when worn, only shreaking when siezed. The next thing to look at is the starter. Lots of people report that the starter gives a short, loud and horrific shreak for about a second as the bendix engages. The fix is to remove the starter and clean off the crud.
That's assuming the neighbours cat isn't missing......