Where a building is situated partly in the district of one local housing authority and partly in the district of another, the authorities may agree that—
the building, or
the building, its site and any yard, garden, outhouses and appurtenances belonging to the building or usually enjoyed with it,
shall be treated for the purposes of the enactments relating to housing as situated in such one of the districts as is specified in the agreement.
Whilst the agreement is in force the enactments relating to housing have effect accordingly.