"I lost all feeling down my right side and the vision in my right eye. I tried to get up off the floor and just couldn't figure out what had gone on. It felt like my right side was disconnected from me.
"Eventually I got some feeling back, got myself up off the floor and upstairs, thinking I would just go to bed and sleep it off. My brother was staying with us at the time and I went in to tell him what had happened.
"I was just speaking gibberish and random stuff.
"He's a nurse back in London and he kicked into action and started checking me for head injuries. He got an ambulance, got me to A&E and they told me I'd had a stroke. I was lucky he was there."
Hamilton was taken to Tauranga Hospital and woke up in the ward the next day.
"It definitely came as a big shock, to my friends and family as well as me. I've since found out it can affect you at any age - it's just more common in older people."
He has now made some lifestyle changes to mitigate his risk factors going forward.
"A lot of it's about changing my eating habits, my diet, drinking, watching my cholesterol, exercise that sort of thing. I'm walking the dog heaps more. I used to have a beer fridge, which has now gone," he said.
"I've always eaten quite healthily but it's more about portion size. So rather than finishing something for the sake of it, I'll put food back in the fridge. I've got a food diary, where I track what I eat and meal plan every week, so I'm not walking around the supermarket putting things in the basket I shouldn't be."
And it's working.
"I've nearly lost 10kg. I'm at 93kg now and want to get down to 80kg by Christmas. You don't necessarily have to make drastic changes to make a difference. I think mine have all been quite minor, small steps towards doing the right thing. It's about taking responsibility for yourself and your health."
Hamilton's advice to others is to be honest with yourself about your health.
"There were a couple of red flags and you realise if I'd got it looked into then I could've avoided this situation. Don't ignore your health. If you have something that's niggling away at you, listen to your body, get it checked out, because it can happen to anyone at any age."
The Stroke Foundation of New Zealand's Midland general manager Cee Kay congratulated Hamilton on his health efforts post-stroke.
"The work Geoff has already done, and is continuing to do, to make healthier lifestyle choices is simply amazing. He is taking better care and this is helping both with his recovery and with his long term health. Awesome work Geoff.
"Three-quarters of strokes are preventable and the Stroke Foundation provides vital awareness campaigns and health promotion programmes, working closely alongside medical professionals. We have dedicated resources and programmes for high-risk groups, including Māori and Pasifica.
"The number one modifiable risk factor for stroke is high blood pressure and one in five New Zealanders have high blood pressure. A staggering one third are not even aware of this.
"High blood pressure can however be managed and controlled. Through regular blood pressure checks and making healthy lifestyle choices, such as reducing your salt intake, taking medication and eating a healthy diet, the chances of stroke can be drastically reduced."