EX3 was the third prototype saloon, clearly with small changes and developments following on from the first two EX prototypes. A photograph from the Lagonda archives by Klementaski taken in 1946 is shown below.  The car clearly in development form with the pre-war style radiator as seen on the V12 and LG6 cars, and the body can be viewed as progression from these cars, bodied by Lagonda in house with its presumably first body. Note also the water filler cap, clearly an old radiator reused by the works.

Do note the earlier registration, 303 PD on this car, also the frontal view with bosoms visible, headlights to the front still in an experimental format and the closed in rear wings and wheel arches.  The car was equipped with a Newton-Bennett centrifugal clutch and possibly a Cotal gear-box as well, with an early LB6 engine with outside timing chain.   This car was used as personal transport by W O Bentley in the early years in the period 1945 through to early 1947.

Prior to 1947, EX3 was sent to Vanden Plas in Blegium as a bare chassis for a new body .   The car was now registered LPF 775 and the frontal aspect of the car has changed significantly with the new oval shaped radiator clearly visible, and low  placed fog lights,  The rear wings do not yet have  stone-guards, and there are wide-topped quarter lights  and two-piece doors.

During the DB era, the experimental chassis was replaced by the works in period, to bring it to a standard spec, and no doubt make it more presentable to a customer.  This car became LAG/50/443/EX3 in 1952, prior to sale. and was sold by the works to Sir Alaister McAlpine of the building group. The car originally had a registration number of LPF 775, but it has not been heard of for over 40 years.

It seems reasonable to believe that there were design improvements from car to car, as testing occured during the development period.