I am re-reading the Inspector Morse novels as a cure for insomnia and have always known that the learned gent drove a Lancia rather than the Jaguar ..... but which one ?
My money would be on a gunmetal or 'blu Lancia' Flavia 1800 or 2000 berlina. I had always thought a Flam until I saw the quote about 300 miles to the tankful (in your dreams, with a Flam). But in that case it has to be a Flavia 1.8 or 2000 berlina - the 50s cars would be too old, the 1500 is too slow, the coupés not dignified enough, and the colours choose themselves.
I have always though the choice of a Mk2 Jag for the TV prog showed what a low state the Beeb was in at the time (actually even worse now...) - wrong colour, vinyl roof was because it was a write-off bought cheaply from a scrapyard (whatever Peter says!), and most of all, wrong kind of car.
In the 70s Mk2 Jags had NO image, and were driven by thugs, petty crooks and bank robbers (on TV and in real life), simply because they were fast, common and cheap (not the ideal car for Morse then!). The idea of someone who loved opera and the finer things in life driving one back then would have been completely preposterous and just shows that the Beeb will have sent some spotty 22-year-old, who knew sod all about cars and cared less, down the nearest scrapyard to White City with £150, which was par for the course for them both then and now (cf. Top Gear). A Lancia as specified by Colin Dexter, however, was right on the money for the character.
What a shame the Beeb had to go and dumb it down. A shame, but not a surprise.
Being brought up in the East End in the 60's if someone had a Mk II Jag we would say he has a 'bank robbers Jag'.