This brings up a question that's been burning in my grammar maven mind: are there different rules for commas here (outside the Oxford comma)? Because I see them used far more liberally here than I did in the States, and it's SO often that I have to imagine the rules are different rather than a national grammar crisis.
For example: "Head chef, John Smith served up a lovely roast." or "I went out, to get a pizza."
That's interesting, and something I haven't noticed here before. As a woman of *cough* mature years, my education in commas may be a wee bit outdated, but it was all in the US. In your first example I would actually
add a comma after
John Smith, since that is an interruption to the flow of the sentence which simply clarifies the term
head chef. I would consider the second sentence to be incorrect since, to me, the comma doesn't belong at all. I long ago gave up the fight and decided to use the so called Oxford comma, despite the controversy over it. However, I tend to have a heavy hand with commas - as a few people may have noticed.

Ironically, I met my husband through a group on Goodreads and, when I became a beta reader for him, commas were a very large part of our editing discussions. LOL - He was such a charmer and so romantic!
