The Byrne family live in Tullow, Co Carlow, and decided to stay overnight in Bewleys Airport Hotel in Dublin to make the early-morning flight.
But that evening, dad-of-four Brendan received a call to say their house had been broken into.
"We got a phone call before 10pm that night to say our home was burgled, a nightmare start to a break away," he told the Herald.
"That brought us down but we didn't tell JP. Dreams came true in Disneyland and we kind of took our minds off it.
"When we got home reality set in when we got the insurance forms."
Brendan and his wife Enisa were determined to enjoy this incredible journey with their children Michael (13), Aaron (11), John Paul (7) and Ellen (4).
And it was a few days before Brendan noticed the missing jerseys.
"We weren't sure what was gone -- there was a lot of stuff was taken including cash and jewellery," he said. "My heart sank for JP because he loves rugby so much he knows all the Leinster guys and waits after every home game to meet his heroes.
"Rugby is his life -- he just loves it. He's devastated, but no matter what, he gives us a big smile."
JP's most precious possession was an Ireland Grand Slam jersey and a personalised Jamie Heaslip No 8 jersey from the 2008/9 season.
"Jamie autographed 'To JP from Jamie'. It was a memorable jersey to have as it was same season Leinster won the Heineken Cup," he said.