Finley Sherwood back at home in Albury after Royal Children's care

And it wasn't like Chantell Johnson and Justin Sherwood were new to parenting. They knew what to expect, Finley being the fifth addition to their blended family.

But their first bub together and Chantell's first girl quickly gained the nickname 'Diva'.

"She cried all the time and was really hard to settle - when she went for her immunisations, we'd say 'Look, she won't stop crying'," Chantell said.

At the five-month mark, the differences between Finley's development and Chantell's other children became more stark.

She seemed overly lethargic and couldn't, or wouldn't bounce on your lap like a usual bub might.

"She couldn't hold her head up anymore - she would be slumping down in the bath, like she was tired," Chantell said.

"Her eyes would cross sometimes and she was always really sooky."

The gut instinct that something wasn't right didn't fade, but babies can't talk and doctors only have so many diagnostic tools.

Finley was considered normal and healthy until it became glaringly obvious that was not the case at all.

On February 21, Chantell and Justin went out for a day at the weir.

Justin's older kids, 19-year-old Emily and 18-year-old Connor, were their usual helpful selves in entertaining Finley and Chantell's boy Jamison, who has all the energy of a typical five-year-old.

Jamison's older brother Ashton had stayed behind, but it was a stellar day by the water for nearly the entire family.

"We took the boat out, had a great time and then came home - we put the boat away and had music going and ordered pizza - Emily and Finley were laying on the ground," Chantell said.

"Justin and I were sitting on the lounge and we were watching them on the floor, and then we saw she was doing these weird movements with her arms and her legs and shutting her eyes.

"I thought, something's not right; she was never a kid who would just go to sleep on the floor.

"So I popped down to her level and her eyes were going everywhere - they were rolling back into her head and she wouldn't focus on me.

"She was having a seizure."

Chantell got Emily to film Finley while ringing triple-0, and paramedics were at their Glenroy within minutes.

"They kind of thought maybe she was having an epileptic fit, so they were telling Justin to lay her on her side and check her breathing," Chantell said.

"The seizure stopped just before the paramedics got there.

"The paramedics took her blood sugar level and it came up as 'low'.

"It doesn't doesn't read under 0.8, so that meant she basically had a blood glucose level of under 0.8, when it should be four.

"We didn't know what that meant at the time."

There wasn't a sense of panic on the way to Albury Hospital, as paramedics syringed glucose into Finley's little mouth.

But after some time at Albury Base, Finley's blood glucose levels still hadn't risen above two.

"They were administering a lot of medicines then, to try and get her levels up, and they would kind of come up but not stay up," Chantell said.

"They moved her to ICU, which they said isn't common for babies at Albury.

"They said, 'If her levels won't go up, you're going to Melbourne'. That's when it sunk in that our baby was really sick."

Two days later, Chantell and Finley were flown to the Royal Children's Hospital in Melbourne - Justin drove to meet them.

While at Melbourne, there was another MET call for Finely - a scary moment for all.

The metabolic team, endocrinology team and specialists in general medicine and genetics were all perplexed as to what was wrong with this baby from the bush.

"It was pretty overwhelming," Chantell said.

"She's a little bit of an anomaly because she can be high and then drop really quickly, and they couldn't figure out why - it probably took a good three and a half weeks for them to work out what she had.

"She'd had an MRI of her brain and the back of her neck, and they did an ultrasound of all her internals and genetic testing."

Doctors had to take bloods when Finley was in a hyperglycemia-type state - but that was risky in itself.

Finally, one of the samples revealed something strange.

"When you're having a hypo, you shouldn't have any insulin, and her insulin levels were up," Chantell said.

"The shows congenital hypoinsulinism.

"Basically, her pancreas secretes too much insulin, which causes her to have hyperglycemia.

"They diagnosed her with HI."

Doctors had suspected early on Finley had the condition, but genetic testing of Chantell, Justin and Finley did not detect the mutation which usually triggers a diagnosis.

"It's really rare - something like one in 50,000 births," Chantell said.

"In talking to the endocrinology team at Royal Children's, they're currently only treating about 15 children Australia-wide with it.

"They have no idea why she has it - normally it's diagnosed at birth, hence why it's called congenital.

"They think she's had it since birth, but it's just been kind of, underlying."

What life looks like now for the Albury family is 20 alarms throughout the day and broken sleeps to ensure Finley receives enough glucose and medication, similar to a diabetic.

Little Finley, now seven months old, has a nasal gastric tube, but that won't be forever.

She may be a transient case, meaning she grows out of the condition, but no one can be sure.

"There's no guarantee she will, so we have to treat her as if she won't," Chantell said.

"It's been a big learning curve. There will be allied health teams, as she has had developmental delays.

"We're lucky - in many cases, babies born with it are very ill and have to have parts of their pancreas taken out."

Chantell and Justin actually had a chance encounter with another HI family towards the end of their five-week stay at Melbourne.

"I went to get a drink from the kitchen at midnight one night, and there was a Dad there," Chantell said.

"It was almost like jail, you're like 'What are you in for?', and he goes, 'Oh my daughter had been to daycare, had got gastro, and because of her hyperinsulinism, ended up at Royal Children's'.

"I said, 'That's what they think my daughter has'.

"They were really lovely and sent their phone number down to my room with the nurse."

So many nurses went above and beyond at the Royal Children's - something Chantell, Justin and their kids reflected on as they sat down to watch the Good Friday Appeal not long after they got back to Albury.

"They just rally around you," Chantell said.

"Being there is a big eye-opener.

"You forget it's a children's hospital - you forget that every patient is a sick child, and you go down the lift and you see the children with cancer.

"And as much as it sucked that we were there, we knew we got to bring our daughter home."

Back on the Border, Finley has blossomed with the right care.

She's happy and chatty, and still a little diva.

But Finley Sherwood now also bears the nickname "sugar baby" in joining the many HI children around the world.