How do the royals of England live to be great ages?

It's all in the genes.

Not all of them do. Princess Margaret was only seventy when she died, and king George VI was only in his fifties.

A lot of people nowadays live to be very old because they are no longer picked off by infectious diseases and things like pneumonia etc, which did for a lot of people before they reached old age in past times.

I'll wager their longevity is entirely due to their consumption of fine organic produce. Even more so since dear Prince Charles established His wonderful organic farm and agreed to supply His produce at an affordable, discounted price to His Royal relatives and friends.

They are in every respect very well taken care of. Princess Margaret and her father were heavy smokers but all the others are not (as far as I know).

Her father died at 52.

Let me reword your question: How do the royals of BRITAIN live to be great ages?

England is only part of our country. England is not a kingdom. The queen is not the Queen of England, she is the Queen of the United Kingdom.

The Royals no doubt have state of the art healthcare.

You MIX n match...NOT of ENGLAND, as you seem to go on and say in the body of the question. Why insult us NON English BRITISH from Wales, Scotland & Northern Ireland....?? They have an EASY life is the answer......BRITISH MONARCHY & has been for over 300 years.......

They have the best medical care that money can buy! Couple that with longstanding pampering by multitudes of staff and all sorts of lackies to attend to all of their everyday tasks and whims for them, and you'll find you have an answer to your question.

They carry on working all their lives

It's all in the genes inherited from their parents that determines their longevity.