The Fifteen is an expensive car but, without an employee for the purpose, an owner who drives it himself is expected to care for its every need, daily. The owner-driver's needs seem to have been considered very carefully and all but one of them met, that is the difficulty in draining engine oil which requires the removal of an undershield. A minor point was that the rear tappet plate was made difficult to remove by having carburettor control springs anchored on it. The newspaper noted that a few drops of oil two or three times a week ensures tappets run for a long time without shake otherwise they soon become noisy. The following good points were noted by "The Times": Accordingly, "The Times" also noted that "it is not necessary to lift floorboards and poke about with an oilcan before a journey". The car was thought to be moderately fast, best run but it seemed to have a minor fault and should have reached . Seating was assessed to be comfortable with unusually generous knee room in the front seat. Of 5-seater owner-driver cars that have been submitted to "The Times" for trial this car, said the reviewer, is the best. He did consider the car a little narrow for five passengers but decided there is sufficient legroom  On the road, he reported, the lively quiet and flexible engine was silky on top and accelerated with real spirit. Though the clutch could grab, the gears were easy and quiet. The car's steering was delightful but its brakes and suspension were only satisfactory. The 15-40-hp, a lightly revised 15.9, was displayed at the Olympia Motor Show in October 1924. The Times noted some trouble had been taken to dampen engine vibration. The engine and separate gearbox were on a subframe. The engine was flexibly held by two sets of enclosed springs at the front end and at the back by semi-circular steel trunnion blocks. These blocks were secured by spring-loaded bolts. This way the engine was held firmly in a fore and aft position but could swing to the limits of the two sets of enclosed front springs. Each body now had four instead of three doors. The rear seats were wider incorporating the space above the wheel arches, the mudguards were built closer to the wheels to reduce mud splashing. The saloon landaulette's solo occasional seat was now a pair and they folded into the partition below the glass division. The 15-40-hp was fitted with Humber-Perrott semi-servo front wheel brakes.