Time for some more answers.
[16] What nickname was given to the Renault 14 and why did it prove highly embarrassing for its manufacturer?
Answer: ‘La Poire’ which translates into ‘The Pear’ in reference to the car’s unusual shape. It was embarrassing because of the car’s propensity to corrode quickly, just like a pear rotting.
[17] Who allegedly said “Pininfarina must not be allowed to run riot here.” and in reference to what was it said?
Answer: Alec Issigonis, when he found out that Pininfarina was being consulted on the design of ADO17, the BMC 1800.
[18] What once highly successful car was tainted with special editions such as Cabaret, Cameo and Calypso in an effort to stimulate sales in its final years?
Answer: The Ford Capri.
[19] Why is this Iranian built version of the Peugeot 405, called the Roa, unique?
Answer: It is based on the floorpan of the former Hillman Hunter model and is rear-wheel-drive.
[20] Which car, produced from 2007-2014, offered the widest spread of engine capacities of any series-production passenger vehicle?
Answer: Mercedes Benz C-Class W204, which had a range of engine sizes from 1,595cc to 6,204cc.
[21] The 1990 Daewoo Espero was a rejected Bertone design proposal for what other car?
Answer: The Citroen Xantia.
[22] Which current Volkswagen Group subsidiary assembled Triumph Spitfires and TR4s in mainland Europe in the early 1960s?
Answer: Ducati. Managing director Giuseppe Montano set up an arrangement with Standard-Triumph to build the sports cars (and possibly some Heralds) at the motorcycle factory near Bologna. They were never made in large numbers, and had no significant specification differences from the British-built cars. However rarity and the Ducati association has made the Borgo Panigale Triumphs highly sought after.
[23] Identify this car:
Answer: SEAT 850 Largo.
[24] Volkswagen abandoned its plan to build a large rear-engined saloon car, codenamed EA128 in the mid-1960’s because of a growing controversy concerning another car from a different manufacturer. What was that car?
Answer: Chevrolet Corvair
[25] Nova Scotian popular television entertainer and small-town lawyer Graham Day never claimed to be a ‘car guy’ while he was Chairman and CEO of Austin Rover Group from 1986 until 1991.
Day, however, had a passion for one particular vehicle which long preceded his involvement in the motor industry, and continues to this day, with several examples owned and restored. Which of these is it?
Chevrolet Corvair Greenbrier
Datsun 240Z
Mercury Comet
Volkswagen Beetle
Volvo Amazon
Answer: Volkswagen Beetle.
[26] Apart from decals, what distinguished the 1973 Volkswagen ‘Jeans’ Beetle from the standard car?
Answer: An orange paint colour, black exterior trim and seats upholstered in denim fabric.
[27] What was the last Vauxhall model to have different sheet-metal to its Opel equivalent?
Answer: The 1978 Vauxhall Carlton Mk1.
[28] Which model names link the following pairs of car and motorcycle manufacturers?
Pontiac and Triumph – Bonneville.
Kia and Suzuki – Stinger
Alfa Romeo and Moto Guzzi – Stelvio.
Hillman and Kawasaki – Avenger.
Lamborghini and Laverda – Jota.
Honda and er… Honda – Take your pick; Ascot, Integra, Jazz, Vigor – there are probably several more, even at a push Brio, a product of Montesa before Honda ownership.
[29] Italdesign’s 1990 Jaguar Kensington, an unsolicited proposal for an XJ replacement, ended up as the basis for a rather more mundane car. What was it?
Answer: 1997 Daewoo Leganza.
[30] Complete the triptych:
Answer: The link is that the three product names are anagrams of each other.
Driven To Write 
Thanks, Robertas. I didn’t get to participate as I was otherwise engaged. Some truly great finds in there 🙂
I must – belatedly – take this opportunity to note that although ‘Festive Frolics’ is posted under my byline, it’s a joint effort by the R&D department [1] within DTW Towers. It’s great to see the DTW Festive Entertainments expanding in breadth and depth with a new international act on the bill this year – reminds me of the Edinburgh Festival Fringe.
Thanks to all who have participated, and my personal apologies for the time-consuming fiendishness of some of my questions.
[1] Robert and Daniel.
As for 26) I was recently allowed to learn that the (first) denim beetle was available in four different colours.