Proceedings have been begun for possession of the dwelling-house of which the tenant or the proposed assignee is the secure tenant on one or more of grounds 1 to 6 in Part I of Schedule 2 (grounds on which possession may be ordered despite absence of suitable alternative accommodation), or there has been served on the tenant or the proposed assignee a notice under section 83 F1or 83ZA (notice of proceedings for possession) which specifies one or more of those grounds and is still in force.