I'm aware of my good fortune that my salary is higher than average, but how come everyone has a £40k car?  My car cost less than 5k cash and it was a significant purchase for me. 
How do they afford it? 
I used to have the M5.  Would have cost £90k+ to its first owner, but when I bought it (5 years old), it was less than £14k.  Cars drop in value SO FAST here, it allows people to get a lot of car for their money.
We always buy used.  Preferably 3-5 years old former fleet vehicles.  And we both get car allowances.  So there's that.  My husband used to have a company car, so he had a new car every 4 years.  Most of my friends have company cars.
What I will say is that 95% of the people you see driving the £40k cars are either:
1.  Company car
2.  A PCP purchase
A PCP loan allows people to have a fancy schmancy car that they do NOT own at the end of the term.  Basically a lease.  Allows people to live well beyond their means.
It annoys my husband beyond belief that I REFUSE a car loan and will only pay cash for cars.  He wants so bad to have something flash.  Too bad honey!