The Solar Photonic Optoelectronic Transformer (SPOT) is one of the components of the SolarBrane, a Building Integrated Photovoltaic (BIPV) system developed by SolarEmpower Ltd. Recently, an optimised design for the optical concentrator in the SPOT has been proposed to further improve its performance. The optimised design uses a dielectric totally internally reflecting concentrator (DTIRC) based on the maximum concentration method (MCM). Firstly this paper, provides an overview of SolarBrane followed by the optimised design of the SolarBrane concentrator indicating the geometrical concentration gain improvement when compared to the current design. An optical gain simulation is then presented, showing the angular analysis of the optimised concentrator in two cases; by varying the front surface arc angle and changing the half-acceptance angle of the DTIRC. From the simulation study, it can be concluded that the optimised design provides higher optical gain when compared with the existing design. (6 pages)