Here, Eileen Mallard, 62, tells the story in her own words...
We all giggled as Dad played us a tune on his tin whistle.
Like most Saturday nights, he’d come home from the pub with a box of chocolates for my mum Monica and lollies for me and my brothers, Robert and David, before playing Irish music.
‘I never felt loved until I met your dad,’ Mum would tell us.
She’d grown up in an orphanage in Dublin and didn’t know anything about her birth family, apart from that her mum’s name was Katie Hall.
In her early 20s, she’d moved to Melbourne where she’d met my dad, who was also Irish, and they’d had me and my brothers.
Over the years I’d wondered about Mum’s family and would often ask if she was interested in tracking them down.
‘They didn’t want me, so why should I find them?’ she’d say.
We were her family and that’s what mattered.
So we were all devastated when Dad passed away aged 87, from pneumonia, in 2014.
Mum had become forgetful but it got much worse after Dad’s death.
She was diagnosed with dementia in 2015 and the following year, when Mum was 87, we moved her to a care home.
We visited all the time.
But now I had to accept that we’d probably never know about her family.
Then a couple of years later, my brother David, then 58, decided to do a DNA test out of curiosity.
One day, he phoned me with some news.
‘Mum has a half-sister called Maureen – and I think I’ve found her!’ he said.
‘What? That’s amazing!’ I gasped.
It turned out, his DNA results had matched with a man in the UK called Martin, who was our second cousin.
Martin had already done a family tree and suspected his first cousin Maureen, also from the UK, was Mum’s half-sister.
Finding her on Facebook, David sent Maureen a message and soon messages were flying back and forth.
Maureen confirmed her mum’s name was also Katie Hall – she was Mum’s sister!
Maureen was thrilled.
‘I haven’t been able to sleep with excitement,’ she said.
She also sent us a photo of their mum.
Peering at the snap of my grandmother, I felt a mixture of emotions.
It was great that Mum would find out about her family, but I couldn’t help feeling angry she’d been put in an orphanage.
Going to see Mum, David and I told her everything.
‘I’ve got a sister? How wonderful,’ she gushed.
‘She’d like to speak to you over Skype,’ I explained.
Mum’s dementia meant we had to explain who Maureen was again before we rang.
But her reaction was just as joyful as the first time.
David, Robert and I were all there as Mum and Maureen saw each other on the screen for the first time.
It was so emotional and I found myself tearing up as I watched them talking.
‘This is the best thing that’s ever happened to me,’ Mum beamed as she chatted away with her new sister.
It turned out that Maureen had a son Matthew who lived in Melbourne and she visited most years.
It was crazy to think she’d been in the same city as us!
From then on, we’d all catch up with Maureen often.
We chatted about Katie and tried to work out why she’d given Mum up.
Maureen had never even known that Mum existed, so she didn’t know for sure.
But she did say that Katie was a bit of a party animal in her youth, and she’d only been 18 when she had Mum.
It was 14 years later, and after she’d married, that Maureen came along.
We had no idea who Mum’s dad could be.
Two months after they’d found out about each other, Mum and Maureen were on another Skype call.
‘I know we haven’t met face to face, but I can honestly say that I love you,’ Maureen told Mum.
It was such a beautiful thing to hear.
In August 2017, Maureen and her hubby John flew over to meet us for the first time.
‘At long last I’ve got a blood relative,’ Mum beamed as she hugged Maureen.
It was such a special day.
We all instantly clicked and chatted away like we’d known each other forever.
Every day, we’d have to remind Mum that she was going to meet Maureen, her half-sister.
But as always, she’d be thrilled with the news.
‘I can’t believe I have a sister,’ she’d say.
Mum and Maureen spent lots of time together, going for dinner and to the beach.
They were always holding hands and grinning.
Maureen brought lots of photos of Katie for Mum to look at too.
‘You look just like her,’ Maureen said.
‘I do, don’t I?’ Mum agreed happily.
In January this year, Maureen flew out again for Mum’s 90th birthday and gave her a gold locket.
‘It’s gorgeous,’ Mum said.
I still can’t believe that a simple DNA test led us to finding Mum’s family – it’s so wonderful that she now knows more about her past.
I’m going to the UK later this year to see Maureen and to meet some other relatives.
Even though Mum’s memory isn’t what it used to be, her face still lights up whenever we tell her that she has a sister.
I honestly couldn’t be happier for her.