Fusi dates an RLS with chassis and engine number 7323 as a 1923 2nd Series RL Sport with matching engine
Available with either a 'Torpedo' (Tourer) or Berlina or Spider body style from a variety of Coachbuilders - Fusi shows a picture of a Weymann bodied Torpedo on page 69
The RL Sport (Series 1 to 5) and RL Super Sport (Series 6 & 7). The RL range was powered by a 3 litre straight 6 with overhead valves and available in a single carburettor RL Normal or the twin carburettor RL Sport which later became the RL Super Sport.
Fusi shows a cast iron finned exhaust manifold with a central pipe exiting downwards, I suspect that the car shown above has an incorrect branch manifold.