How can I check if a used car attracts a tax premium?

When buying for example a two year old car is the seller either private or a dealer obliged to inform you that when new it's list price was over 40k and is therefore subject to the extra premium tax until...

Does the premium car tax £40,000 rate include options?

If I purchase a new car sub £40,000 it is not subject to luxury tax but if I add options which take it over 40k is it liable to the luxury car tax?

How long do I have to pay premium tax?

Currently my road fund licence is £600,00 per annum how many years will I have to pay this high rate of road tax for? Does it fall to the normal level of road tax after this initial period?

What happens to premium rate VED once my car is six years old?

I bought and taxed my car in Jan 2024. It was first registered in May 2019, and had a list price above £40k so for 2024 I paid the additonal tax rate. Since the car will be 6 years old in May 2025 can...