That expression could be improved slightly.

/^(?:\d|\d\d)\s-/

(?:\d|\d\d) can become \d\d? - the "?" means that the second digit is optional, so it can be there but doesn't have to be.

\s will match any whitespace character ($cr, $lf, a tab, etc) so it's better to just use a space.

/^\d\d? -/