one sign - and the best, is along aberdeen street, the sign is attached to the side of the aberdeen hotel - or maybe it is called the "deen" - in northbride. the other sign, is the bgc sign, and is best seen from the southperth foreshore - , just look - you cannot miss it - it is mostly blue, when in shows BGC - but then it shows a few other things as well
hope that helps a bit