berty – The one month Notice is sufficient time.
The agent, rather then the owner, has contacted you because the owner has given the agent the authority and responsibility to do this via the agency agreement.
In the circumstances of you working (and if you are uncomfortable having an unaccompanied trade person in your apartment in your absence) may I suggest that you either: (a) organise for a person that you know to be in attendance when the work is carried out, or (b) obtain a written guarantee that a Executive Committee member will be onsite in your apartment with the installer at all times, or (c) organise for the agent to be in attendance when the work is carried out, or (d) ask the owner to be in attendance when the work is carried out.
The Office Of Fair Trading states, in relation to owner or agent access, that:
“The law says that tenants must not deny or hinder your right to access if proper notice has been given. If your tenant refuses to allow you access to the premises, an application can be lodged with the Tribunal seeking an order allowing entry.”