As Harry moved into his late teenage years, life was changing. School was coming to an end, adulthood was getting closer, and that cheeky little lad who was always getting himself into mischief was growing into a young man with his own ideas about how he wanted to live.
After leaving Goffs in 2016, Harry initially went to college, but it didn't take long for him to realise that sitting in a classroom wasn't really for him.
Harry was much more of a hands-on person. He preferred getting stuck into something practical rather than learning from books, and before long he found himself working on the tools.
Through family and friends' businesses, Harry began learning different trades, including painting, decorating, plastering and roofing. He wasn't afraid of getting his hands dirty, and these experiences helped him find his feet in the working world.
But while Harry was busy learning new skills and growing up, another side of his personality was becoming even more noticeable.
This was around the time that Gully was born.
The story behind the nickname was about as typical of Harry as you could imagine.
One day, seemingly out of nowhere, Harry started referring to himself as "The Gully Man", proudly claiming that he got all the "Gullys" - his own way of saying girls.
Nobody had given him the nickname. Harry had simply decided it was his!
What probably started as a bit of a joke soon caught on amongst his mates, and before long, Gully became the name everyone knew him by.
Over time, Gully developed into Gully Woo, and the name became part of something even bigger.
With football already playing a huge part in Harry's life, a Sunday league team called Woo United was formed. The team brought together many of Harry's closest mates, with his older brother Mike helping Harry establish and run it.
It was about more than just football. Woo United gave the lads another reason to get together, have a laugh and make memories, with Harry right at the heart of it.
Harry's love for Arsenal was also as strong as ever. Having supported the club since he was around four years old, following the Gunners had become a huge part of his life.
During these years, he began attending more matches alongside his friends Cicco, Cam, Jack and Joe. From home games to away days and even European trips, watching Arsenal became another way for Harry to spend time with his mates and enjoy the experiences he loved.
And then came his 18th birthday in June 2018.
For Harry, turning 18 meant one thing in particular: even more opportunities to get out, socialise and enjoy himself.
He loved being around people, having a laugh and making the most of whatever was happening. Whether it was football, a night out or simply spending time with his mates, Harry was happiest when there was something going on.
At 19, he headed off to Magaluf for his first lads' holiday, another milestone in his journey towards adulthood and the beginning of a new kind of adventure.
His sense of humour hadn't changed much since childhood either.
By now, Harry had developed a particular response for anything that didn't quite impress him. Rather than argue or make a fuss, he'd simply give a sarcastic "Woo."
It became one of those little Harry-isms that people who knew him would instantly recognise.
Despite his growing independence and busy social life, family remained important to Harry. He loved spending time with his mum and younger sister Maddison, continuing to be a loving big brother as she grew up.
These were also the years when Harry began looking more towards his older brother Mike for guidance as he found his way into adulthood. Their relationship was growing alongside them, moving beyond the childhood years into a different stage of brotherhood.
Between 2015 and 2020, Harry was beginning to build a life around the things that mattered to him: his family, his mates, football, work and having a good time.
He might not have followed the most traditional route after school, but Harry was finding his own way.
And somewhere along that journey, the cheeky little boy from Stevenage had become the young man everyone knew as Gully.
A nickname he'd made up himself, a football team built around his closest mates, and a personality that people wouldn't easily forget.