Mild Cognitive Impairments (MCI) disrupt the quality of life and reduce the independence of many elderly at home. People with MCI can increasingly become forgetful, hence solutions to help them finding lost objects are useful. This paper presents a framework for mobile robots to localise objects in a domestic environment using Radio Frequency Identification (RFID) technology. In particular, it describes the development of a new library for interacting with RFID readers, readily available for the Robot Operating System (ROS), and introduces some methods for its application to RFID-based object localisation with a single antenna. The framework adopts occupancy grids to create a probabilistic representations of tags location in the environment. A robot traversing the environment can then make use of this framework to keep an internal record of where objects were last spotted, and where they are most likely to be at any given point in time. Some preliminary results are presented, together with directions for future research.