The CGT legislation defines a wasting asset as something with a predictable life not exceeding 50 years. And "life" means useful life, having regard to the purpose for the person making the disposal acquired the asset.
If you buy a vintage car or an antique watch that is already 50 years old, obviously that's not a wasting asset. And if you buy a car or a watch that's, say, 45 years old, you're probably not buying it to commute to work or to tell the time. You might be buying it because you just want the pleasure owning it; you want to gaze at it adoringly and think "this is mine!". You can do that long after it turns 50, so it's useful life is more than 50 years and its not a wasting asset.
What about the case where you order a brand new Porsche GT3, intending to sell it on as soon as it's delivered in, say, 2 years' time, and confident that you will profit by doing so? Arguably, that's still a wasting asset; your purpose of quick resale will not endure for 50 years and, while a Porsche might well be on the road for driving purposes 50 years after it is delivered, statistically speaking the majority of them won't be. So you've a good argument that what you've got here is indeed a wasting asset and that, when you sell it on, your gain is not within the charge to CGT.
But you have a different problem. The little-known Schedule D Case I makes income resulting from "an adventure in the nature of trade" chargeable to income tax. You're not carrying on a trade of dealing in cars; a single purchase-and-sale is not a trade. But it can be an adventure in the nature of a trade, if you bought the car predominantly with a view to making a profit on resale. So you may find you have leapt out of the CGT frying pan into the income tax fire.
Your best bet is to order the car with the intention of taking delivering and driving it for pleasure. But then, to your complete surprise and astonishment, shortly after taking delivering you receive an offer for the car that's just too good to look past.