(a) Any person or persons, jointly or severally aggrieved by any decision of the board of adjustment, may, within 30 days after the date of the public hearing at which the decision was rendered, but not thereafter, apply to a court of competent jurisdiction for appropriate relief.

(b) The board of adjustment shall not rehear a variance once decided unless an error in substantive or procedural law is found following the decision, or unless the board of adjustment makes a finding based on a presentation by the applicant that new evidence, not discoverable by the applicant prior to the initial hearing, is found. A different or more effective presentation or clarification of the same evidence or matters considered at the initial hearing shall not be grounds for a rehearing before the board of adjustment.