From 2013 to 2019 Aussie McLean was an undercover agent for the All Blacks. It wasn't anything like a glamorous James Bond movie.
In the cause of All Black rugby he was soaked in beer in The Zoo at Forsyth Barr Stadium in Dunedin, hitched a lift with strangers toa test in crime-ridden downtown Johannesburg, and merged into crowds from Auckland to the Andes.
During Steve Hansen's time as national coach McLean morphed from defence coach in 2012 and 2013, when he was always with the team, to being a tactical analyst, often flying solo to the other side of the world to quietly check out the opposition.
There were no McLean interviews. You never saw him in the rarefied air of the coaches box. Instead he was in plain clothes, sitting anonymously at the end of the ground, a notebook in hand, taking copious notes.
"When you're side-on you can't see who's too narrow, who's too wide, who coming in to tackle, who's pushing out to tackle, who's able to be manipulated," McLean, now living at Clearwater in Christchurch, told me.
"I was there to get my picture of what was happening, the strengths and weaknesses of both the opposition teams and us. Then we'd look at the video to make sure we were on the right track. It was more tactical than technical. I would never venture into the scrum or lineout drives."
It was a new unpublicised role. There was the man at Eden Park who asked him, "Are you a journalist?" No, said McLean, he wasn't. "In the end I said, 'Actually I work for the All Blacks, doing analysis.' The guy asked, 'What are you seeing?' I said, 'Sorry mate, I've got to concentrate on the game.' Thirty seconds later he said, 'Would you like a beer?'"
The trust Hansen had in McLean dates back to the 1970s, when Hansen was just 17, fresh from captaining the Christchurch Boys' High First XV, and McLean was the 24-year-old vice-captain of the Christchurch Marist senior team, coached by Hansen's father, Des. McLean is one of many in Canterbury who remember Des, who died in 2012, as a rugby guru.
"Des taught me about the game. I'd go there on Friday night and have dinner at the Hansens and talk rugby with Des the whole time. He taught me cause and effect. 'You always know your own position reasonably well. I'll teach you about the other positions.' We had nine first-class rugby coaches comes out of that team coached by Des. It's no coincidence."
Teenage Steve had his own strong theories about the game too, at a time when in rugby teams new kids were expected to just shut up and listen.
"I could see his ideas were pretty good," says McLean. "So I said, 'You pass them through me and I'll sell them to the team'." McLean jokes. "It wasn't that long before if I had an idea, Steve would sell it to the team, and that's really how it's gone for the rest of my rugby career."
McLean would forge his own impressive resume as a coach. His first big job, as an assistant coach with Canterbury, saw the Ranfurly Shield won from Waikato in 1994. In four years as Canterbury's head coach from 2002 the team won two NPC titles, and in his one year coaching Wellington in 2007 the side made the NPC final.
But his greatest success came in a role he enjoyed the most, coaching the Under-19 New Zealand team to world titles, with teams involving future All Black stars like Kieran Read, Jerome Kaino, and Joe Rokocoko. "At that stage the kids need to be taught. At All Black level a lot of the teaching has been done."
McLean's All Black role, which involved his independent analysis of the All Blacks as well as their opponents, would end at the 2019 World Cup in Japan. The campaign started brilliantly, with a 23-13 win in pool play over eventual winners, South Africa. But in the semifinal in Yokohama the All Blacks lost 19-7 to England.
Ask McLean today if complacency played even a tiny part in the All Blacks' loss to England, and his answer is immediate. "God no. From 2015 I'd been telling Steve that England would be our biggest challenge. They'd won the world Under-20 titles in 2013 and 2014 and by the time 2019 came around they had very good players available.
"Had our lineout functioned as we would have expected it to, we would have had England on the back foot. The English really only had two jumpers, while we had at least four excellent lineout options. But our lineout just didn't function as well as we had expected. That meant England got us on the back foot at first phase a lot, which put us in a difficult position for long periods of the game.
"I'm not sure what we could have done differently from that position. Had we dominated on our own lineout ball and put a lot of pressure on their ball, which we thought we would, we would have been going forward, and nobody would be talking about our selections."
McLean also points to the midfield as a reason for the semifinal defeat.
"The other thing is that ever since Ma'a Nonu went we haven't had a really physically dominant person in the midfield.
"Since Ma'a's gone we've had guys who are really good rugby players. But our problem is that most of our midfield players who have been the form players in Super Rugby have been very similar types. You need someone who's the ball carrier, and one who's an organiser. Our great teams have always had centre pairings who are like ying and yang. Walter Little and Frank Bunce, Joe Stanley and Warwick Taylor, Ma'a and Conrad [Smith].
"Ma'a was also a good passer. When I coached him at the Hurricanes I kept wondering, 'Why doesn't he pass more? He'e a really good passer.' But I knew that every person who had coached him knew his great strength was carrying the ball not into contact, but right through it.
"He never got asked to change, because coaches decided we'll use your strength. And in his early days especially, a lot of his self esteem came from rugby, and in rugby his self esteem came from his ball carrying. And God, he was good at it. You'd have tackling practice, and no-one wanted to tackle Ma'a. He certainly used his full range of skills at the back end of his career.
"Now we're seven years on from 2015 and we still haven't been able to establish a centre pairing."