Robert, 41, is a dad to four girls as well as a full-time carer for his eight-year-old daughter, Cerys Lily, who has autism.
He'd originally gone to Argos to buy a new bedside lamp for Cerys Lily, but when she noticed a display of Finding Dory lunchboxes that weren't actually on sale until the next day and therefore couldn't be bought, she had a 'full meltdown'.
'Because she is autistic she doesn't see life as we see it,' Robert told the Mail Online, explaining how his daughter could not really understand why she wasn't allowed to have the lunchbox.
He had to carry her out to their car and take her home, where she could calm down, only to have two police officers - PC Steven Bowen and PCW Leigh Francis - knock on his front door 20 minutes later. Someone had mistakenly reported Robert for putting a child in his car against her will, not realising that he was Cerys Lily's father.
After explaining to the officers about his daughter's autism, they immediately sympathised with his situation, particularly PC Bowen who completely understood as his own nephew has Asperger's syndrome. The police pair even put on their car siren and flashing lights for Cerys Lily!
To Mr Davies' amazement, PC Bowen and PCW Leigh returned the next morning with a surprise gift for Cerys Lily - her very own Finding Dory lunchbox.
'When I opened the door, the policeman was standing there and then pulled out the lunchbox from behind his back. It was really quite overwhelming,' said Mr Davies.
'Cerys Lily was sitting on the stairs to see who was there and she couldn't believe it either. She just said thank you in a soft voice. I think she was also quite taken aback.'
His post thanking the two officers has now been shared over 3,600 times.
'After they pulled off I felt I hadn't thanked them enough so that's why I posted it on Facebook.'
Many people commented on the post, thanking him for sharing such a heart-warming story and, as Christian Thomas wrote, 'restoring faith in humanity'.
'I'd like to thank 2 officers PC Steven Bowen and PCW Leigh Francis who went beyond their call of duty for my daughter... there really are some good people out there.'