As stated before, the officially designated Bren Gun Carrier was long obsolete by this time. The vehicle on the left is the replacement that was designed to fill the role of all "carriers" and was designated Universal Carrier. However, the general public, being unaware of this change still called any carrier a Bren Gun Carrier. Although hard to make out at this size, this carrier appears to have a Vickers MG mounted on the engine cover.
The vehicle on the right is a completely different type, being called a Loyd Carrier. Its most obvious distinguishing features are a straight glacis plate, four road wheels and the driven axle is completely exposed at the front whereas the Universal had three road wheels and its driven axle was at the back.