64B. (1) For the purposes of this Chapter, a Part 4 tenancy and any further Part 4 tenancy entered into following the expiration of —

( a ) the said Part 4 tenancy, or

( b ) a further Part 4 tenancy,

shall be treated as one tenancy, and references in this Chapter to duration of tenancy shall be construed accordingly.

(2) This section is without prejudice to subsection (2) of section 61 . ]