Right. I’ve had enough. If you were to ring Harrods and say you wanted to spend £100,000 in their luggage department, I wouldn't be at all surprised if they sent a car and gave you a genuflecting personal assistant with a PhD in obsequiousness.

But if you were to ring a car dealer and say you wanted to spend £100,000, they’d put you on hold for half an hour. After which you’d be put through to a disinterested yob with nasty hair and a cheap suit who would explain that they have no demonstrators at the moment so maybe you could pop in some time later on the off chance.

When you do, you’ll be told there are still no demonstrators, that the windscreen wipers are optional extras, that you can have it in a choice of only five colours — all of them ghastly — and that delivery is expected some time in 2008.

And this is for a car costing £100,000, so I dread to think how shabbily you are treated if you “only” want to spend £15,000. Frankly, I’d be surprised if you could get out of the showroom with your life.

Let me give you an example. Last week, while driving around in Vauxhall’s little Tigra, I ran over a screw. This meant the tyre went flat, which in turn meant I had to pull over and change the wheel. Hard, because there was no jack, and doubly hard because despite what it said in the handbook there was no spare wheel either.

All you get is a can of foam and a set of instructions that explain what to do with it. Step One, apparently, is to remove whatever it is that caused the tyre to go flat in the first place.

How? How do you get a one-inch screw from a tyre when you’re on the side of the A3, where there’s no hard shoulder, and shucks, you’ve gone and forgotten your handy Swiss Army knife?

Still. No problem. You’ve spent nigh-on £15,000 on this car so obviously Vauxhall will bend over backwards to ensure a new wheel and tyre are delivered as soon as is humanly possible. Well, yes, but unfortunately they don’t actually have any tyres for this car in the country at the moment, so would you mind awfully just waiting by the side of the A3 until they do? We should be able to rush a set over from Germany in a couple of weeks.

Now bear in mind, please, that I’m talking here about the Vauxhall press office, who knew damn well that I was driving the car and that I would be writing about it in The Sunday Times. They also knew I was on my way to the Top Gear studio to record a show. And they still couldn’t help, so what possible chance have you got?

Vauxhall isn’t alone, either. I found out recently that Volvo doesn’t bother keeping a stock of spare tyres for the XC90 in Britain, and I’m sorry, but this isn’t even half-way good enough.

The XC90, at the bare minimum, is a £26,000 car and that’s way above the average income for most people in this country. So I would expect all spare parts to be available, anywhere in the country, within the hour. Actually, for £26,000 I would expect the tyre to be delivered on a silver tray by a butler in tails, arriving by helicopter.

It never happens, though. Every day my mailbag is stuffed to overflowing with letters from desperate people who can’t even get their dealers to be civil, leave alone helpful. I know one chap who became so disillusioned with his Mercedes garage he parked his car right across the entrance to the forecourt and refused to move it until they found the spare part that hadn’t turned up for nine weeks.

Mind you, this is Mercedes and they’re off the bottom of the scale when it comes to customer satisfaction. The prisoners in Camp X-Ray are treated with more compassion. Pol Pot wasn’t a Mercedes dealer, but he certainly had all the right credentials.

I must say at this point that my local dealer has taken on a chap who buys my wife flowers and knows my name, and I should also say I rarely hear bad things about Jag or BMW dealers. But that said, I don’t hear good things either. I don’t hear about children’s birthdays being remembered, or Fijian dancers being sent round to rub exotic oils into your shoulders — some of the things you’d expect when you’ve just given them the equivalent of Brazil’s national debt.

The message, then, is clear. Car dealers need to sharpen up their act. They need to moan with pleasure when we walk through the door. They need to compliment us on our clothes, our hair and the firmness of our bodies. They need to watch that “obscene amount of money” scene from Pretty Woman. And then they need to watch it again. And if I decide to relieve myself in their rubber plant, they need to praise me for my accuracy.

Now, with that all sorted out we can move on to the Tigra itself, which is a surprisingly good little car. If you don’t want to go anywhere.

The problem here is that Vauxhall is offering, on a £13,750 car, the sort of complicated electric folding metal roof you get on a Mercedes SL. Now the sheer number of motors and pumps needed to make this kind of thing fold away quickly and reliably means that it’s a very expensive piece of kit.

So what you’re actually buying is a great roof with a very small amount of car attached to it. You certainly get a very small amount of engine, which leads us on to another issue. Weight.

That roof is going to tax even the mightiest of V8s so it’s more than a match for the 1.4 litre vacuum cleaner engine Vauxhall put under the bonnet. On even the gentlest of inclines you really need to select fourth or even third to have a hope of maintaining any sort of forward momentum at all.

This presumably is why they’ve ditched the spare wheel. Partly because for £13,750 they can’t afford to fit one, and partly because any extra weight would slow the car down to a point where it became, technically, a garden ornament.

The funny thing is that I don’t mind. If you want to have a bit of pep you can spend an extra £2,000 buying the 1.8 instead, which will whizz you along at 127mph, although to be honest I wouldn’t bother.

You see, the Tigra isn’t really designed to tear your eyes out on a challenging B-road. It’s not supposed to put the wind in your hair so much as a gentle breeze. And that makes it more a sort of urban runaround — small, easy to park, cheap to insure and inexpensive to mend. But unlike any other small cheap car of this type, the roof comes off — and it looks fabulous. Really fabulous.

Even though it comes with a Vauxhall badge, which is awfully embarrassing when people ask you at parties what you drive, I think I’m right in saying that this is the first small open-topped car I’ve driven in the past eight years that is better than the Mazda MX-5.

Some say it’s a bit girlie, a little like going to work in a blouse. And I think I can sort of see what they mean. I couldn’t for instance see Sean Connery in a Tigra, or Ray Winstone for that matter.

That, though, isn’t the end of the world, especially if you’re the kind of girl who can’t change a wheel, because of course it doesn't have one.

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