"in 1994, 6.3 per cent of cars on the road were over 13 years of age...(in 2019) the percentage of vehicles over this age is 19 per cent."

"according to the research, the average age of all cars on UK roads has increased from 6.7 years in 1994 to 8.3 years in 2019."

https://www.thisismoney.co.uk/money/cars/article-8739771/Bri...

So the average car is getting older, but still far from 12 years.