Where a housing authority—
request—
another housing authority ;
the Greater London Council;
a development corporation ;
the Commission for the New Towns ;
a registered housing association ; or
the Scottish Special Housing Association
to assist them in the discharge of their functions under section 3, 4 or 5 above, or
request a social services authority or a social work authority to exercise any of their functions in relation to a case with which the housing authority are dealing under section 3, 4 or 5 above,
they shall co-operate with the housing authority in rendering such assistance in the discharge of the functions to which the request relates as is reasonable in the circumstances.
Paragraph (a) of subsection (1) above shall have effect in relation to a housing authority and the Greater London Council as if the reference to sections 3, 4 and 5 above included a reference to section 7 above.