Validation of acts and proceedings

No act done or proceedings taken under this Chapter shall be questioned on the ground merely of—

1. (i) the existence of any vacancy in, or any defect in the constitution of the Local Development Authority;
2. (ii) any person, associated under section 69 having voted in contravention of the provisions of this Chapter in this behalf;
3. (iii) the failure to serve a notice on any person where no substantial injustice has resulted from such failure;
4. (iv) any omission, defect or irregularity not affecting the merits of the case.