So what is the role of Under-23 football?
“We are just trying to develop and help them as much as we can. We've been really happy with the development of a lot of the boys. You learn it's not all about results, although it's hard not to look at them.
“You've got to look at the development of individuals, like Michael Folivi, Carl Stewart and Brandon Mason; Dennon [Lewis] and Alex [Jakubiak], who are both out on loan. Hopefully that is where we are affecting the boys in readying them for the next step in their journey, which is first-team football. It's not easy but if we can help, then great.”
Mullins, 37, looked after the loan players at Reading before he moved down the M4 and round the M25 to London Colney last summer.
“The one thing I've struggled with in Under-23 football is that it's really nice on the eye, but it needs to be realistic. You need to get them ready for the first-team.”
Mullins was readied for his playing career, one that spanned 562 league starts mostly in the top two divisions, in an old-school way.
“It was completely different and was a lot harder than today,” he says.
“It was tough. We'd get in an hour before everyone else, make sure the place was clean, you'd make sure the pro's kit was ready for him and that his boots were done before he got in otherwise he'd nail you for that. I used to clean the boots of Dean Gordon and John Salako.
“Only once you’d done all that could you have your breakfast. These boys are privileged: they don't really have to do jobs. I'm old school, it should be back to the way it was. It keeps you grounded and humble at a time when there is a lot of money in the game, you can take your eye off the ball.”
Mullins has all the badges but, like Kewell, he’s very much learning on the job and at an embryonic stage of his coaching career.
“I want to learn here and improve and get better. If the opportunity arose, one day, I'd love to do first-team stuff, whether that would be here or somewhere else. I'm more than happy here and working with the Under-23s. Me and Harry love what we do and we are very passionate about it. It's a tremendous place to start.”
Mullins has spent his career around the training grounds of West Ham, Portsmouth, Crystal Palace, Reading and Birmingham, so is handily placed to judge how Watford are faring in their attempt to establish themselves among the game’s elite.
"It's a fantastic set-up,” he says. “The boys get the treatment. The food is fantastic, the pitches we use are unbelievable and we've got a little stand now for our match pitch. The club is geared to kick onto the next step and push forward and maybe look at European football."