The classic Mini market has shifted in the last couple of years. Not so long ago, the ideal old Mini was a perfect original from the 1960s, but there's a rapidly growing trend towards buying middle-aged cars, retaining or even enhancing the 1960s look while modernising them technically. There are large numbers of cars which survive from the mid-1970s and are ripe for this treatment, giving a second wind to the Mini market. This fashion is strong in the USA and prosperous parts of Europe: customers will spend, typically, £5,000 to £10,000 on rebuilding a relatively inexpensive old car that will be fundamentally re-developed for the modern world. You can have a cheap and cheerful classic or, like one man in the USA, order the ultimate hot roadgoing Mini, using all the best bits and tricks that have been developed over 40 years; this enthusiast has accepted that the finished car will cost him more than £24,000. Standing perhaps a little aloof from all this fun, the Mini purist still regards a Mini Cooper 970S from 1964-65 as the ultimate and will pay what it takes, probably up to £10,000, to obtain a perfect example.

The 1275S of the same era is worth up to about £8,500, while the 1071S of 1963-64 might be £1,000 cheaper even though it is reckoned to be the driver's choice for pure fun behind the wheel, thanks to its almost unburstable short-stroke engine. The years 1963-65 marked the golden era of the Mini Cooper. Earlier Coopers were not that fast. The least desirable seems to be the 997 which came out in 1961 and is now worth up to about £4,500; the small brakes and long-stroke engine go against it. Later Coopers don't have quite the same appeal to the traditionalist but an exceptional 1275S from 1966-71 might still fetch £7,000.

A few very early original 850s can still be found as perfect cars for £3,000-£4,000. Remember, however, that despite their undoubted charm these bog-standard models are still too slow to stay with a good 2CV on a motorway. Oddities such as half-timbered Travellers, Pick-ups and Minivans are going up sharply in value but, like the best Coopers, decent examples are very hard to find. These days, enthusiasts and dealers hunt down all worthwhile old Minis and you have to move fast to secure the best examples. But beware: check, especially with Coopers, that what you are buying is the genuine article. Such checks can be done through the Heritage Motor Centre: for a small fee it will look up the production records and issue a brief document confirming the car's origins and specification.

With Mini Coopers, the non-profit-making Register will help spot the fakes, too. Whichever path is chosen, a brand new replacement Heritage Mini bodyshell is the ideal basis for such a project, but it will need the skills of a specialist to build it up. Introduced a couple of years ago, this bodyshell is at heart a MkIV from the 1990s, created with subtle changes to make it look like something from the 1960s. It has the early rear end styling, for example. Just pause here for a moment's thought: all this Heritage organisation grew up spontaneously, irresistibly, under Rover. It all survives, but not as an integral concern. When you check your Mini chassis number you will consult the fine new Heritage Museum at Gaydon, now under Ford Motor Company control. If you buy a Heritage body today, it will be from stocks freshly made at Longbridge under BMW. But, as we all know, production of the old Mini has just ended and the all-new BMW MINI will be made at Cowley, Oxford. British Motor Heritage, formerly an arm of Rover, has a strong commitment to the classic Mini and is currently putting the finishing touches to its permanent Mini bodyshell production shop in its specialised factory at Witney.

It is "specialised" in that it retains the old skills required, the skills of an earlier stage in the history of the mass-produced car. There they also make MGB, Midget and Triumph TR6 bodies, plus millions of parts for many other favourite classics: a popular new line is front and rear Mini subframe assemblies, completely built up and ready to bolt on any post-1976 Mini. Curiously enough, these activities are all under BMW: relatively small though it is, nevertheless the subsidiary British Motor Heritage does make a modest but steady profit and is expanding. These are encouraging facts. Available from BMH is a list of Heritage-approved Mini specialists, UK and worldwide: these specialists, and indeed all Rover dealers - at least in theory - can provide the major parts and trim your classic Mini will need to preserve and improve it. Who knows what the future holds for the extraordinary maze presented by the world of classic Minis?