Where the dwelling-house is reasonably required by the landlord for occupation as a residence for some person engaged in his whole-time employment, or in the whole-time employment of some tenant from him or with whom, conditional on housing being provided, a contract for such employment has been entered into, and the tenant was in the employment of the landlord or a former landlord, and the dwelling-house was let to him in consequence of that employment and he has ceased to be in that employment.