A rare and beautiful left hand drive Mercedes-Benz W124 A320 Cabriolet - believed to be the only example built - is certain to attract International interest from collectors at this year's Melbourne International Motor Show auction conducted by Shannons on March 12.

The imposing 5.5 metre long car with its 3.4 litre six cylinder engine and full coil spring independent suspension, was originally built by Daimler-Benz around 1948 as a design study for a future luxury cabriolet model.

As the company then had only just recommenced production after the devastation of World War II, the vehicle employed the 59kW side-valve engine and a number of other mechanical components from the last of the W142 long wheelbase Mercedes-Benz luxury cars manufactured from 1937 until hostilities and factory damage halted production in 1942.

However the evolution of the much more modern single overhead camshaft engine and other technical developments that materialised in the A300 (Adenauer) saloon of 1950, rendered the cabriolet design study redundant and the vehicle was sold to a Dutch businessman and shipped to Indonesia.

It remained in Indonesia for almost 40 years before being discovered by accident by an Australian enthusiast and brought to Melbourne in the late 1980s.

It arrived in very poor condition, badly painted in Post Office red and in non-running order, but an inspection by visiting Mercedes-Benz Museum head Max-Gerritt von Pein confirmed its unique status and gave impetus to the total restoration that followed. He was amazed that not only had the vehicle survived, but that it was in basically its original condition.

The work to bring the cabriolet back to its factory design study originality involved a full strip-down to the bare chassis, during which clues to the car's original two-tone blue paintwork were found under the door hinges and the vinyl trim covering the original matching two-colour leather trim was removed.

Using local Melbourne tradesmen and specialists, this rare vehicle has now been totally refurbished bodily and mechanically to as close to its original specification as possible, with the painstaking work only completed early last year.

Because of the vehicle's imposing style and rarity, Shannons are expecting bids in the $450,000-$600,000 range at the Melbourne International Motor Show Auction, which will take place in the Concourse area of the Melbourne Exhibition Centre from 2.30pm on Monday, March 12.