Firstly, ensure that the agent you are getting to represent you, is fully qualified.
All estate agents must be registered with the EAAB and in possession of a valid Fidelity Fund Certificate. Be sure to ask to see the certificate to verify it.
Then, establish whether you are dealing with a full status agent or an intern. Interns will require the cooperation and working with a full status agent to provide their services.
It is always best to deal with an area expert, so it is important to establish how long the agent has been operational in the area and what their track record has been over that time.