A court allowing a bill of review may award an injunction to the decree to be reviewed. But no bill of review shall be allowed to a final decree, unless it be exhibited within six months next after such decree, except that a person under a disability as defined in § 8.01-2 may exhibit the same within six months after the removal of his disability. In no case shall such a bill be filed without the leave of court first obtained, unless it is for error of law apparent upon the face of the record. Notwithstanding the provisions of this section, no court shall allow a bill of review for a decree entered pursuant to § 58.1-3969 to sell real estate to enforce the lien for delinquent real estate taxes.