Jeremy is already identified in the same log sheet as 'Mr Bamber'. If they were in conversation with 'Mr Bamber' it would say such. 'Mr Bamber' is not 'a person'. 'a person' is yet to be identified.
Different people are providing the information and Bonnett and West were not there to see who was being referred to. The only times he would have been referred to as Mr Bamber was if the person relaying the info, notified them of such.