Sue, 65, and her husband left the UK to visit her sister in Auckland, as part of a two-month trip across New Zealand and Australia, on March 5.
Two weeks into their trip, they found themselves in New Zealand, in lockdown — and she did not mind that unforeseen change to her circumstances.
"We've been having a wonderful time here," Sue said. "We've been spending lots of time together drinking wine and cooking and having fun."
According to Margaret, the two sisters have been spending quality time catching up.
"It's been great. It's really hard, as you probably know, to share a kitchen with someone. But we seem to manage; everything works," Margaret said.
It was only in 2000 that Sue found out she had an older sister. Her dad told her he'd had a child with another woman before he met her mum.
"My dad asked me would I try to find Margaret because he wanted her to know there's never been a day gone past when he hadn't thought about the child that had been adopted," she told the BBC.
"He was very regretful that somebody had been brought into the world and he didn't know them and he wanted to apologise for that."
She gave the General Register Office in the UK her details and searched ancestry websites. However, she was warned she would not be given any information unless Margaret got in touch saying she wanted to be found.
She'd always known she had been adopted. After 45 years living in New Zealand and without any real interest in hearing from her birth family, she began to wonder whether she had any siblings.
And just like that, the sisters could formulate a plan to meet.
"I was sitting there in bed with my first morning cup of tea with John snoring next to me and I opened this email and I was like, 'Oh I've got a sister'," she recalled.
"So when he woke up he found me sitting in bed with my cup of tea sobbing. When I told him he was delighted as he has two older brothers. I always wanted to have brothers and sisters but I never did."
Margaret emailed Sue and the two began to hatch a plan. Sadly, their father died before he could meet his eldest daughter.
"Receiving that email was like winning the pools. I would've loved to have told my dad but I just kind of feel he's inside me and he knew it was happening," Sue said.
Along with their two brothers, Lawrence and John Connell, the siblings had their first reunion in the UK last year.
Sue and Margaret could never have guessed they'd be spending a longer period locked in the same house together.
They're now taking time to find out more about each other, and the similarities continue to show.
They both liked their coffee weak and suffered from "wobbly knees", they said.
Sue and John's daughter, who is a doctor, in the UK, advised them they would be better off staying in New Zealand.
"She says stay where you are, it's very safe in New Zealand. But we've got children back in the UK and grandchildren. It's a hard decision. Your heart is pulled to come back. We need to get back really but we're having a wonderful time," Sue said.