The signs are all there
Dudley and Piers' daughter Delilah is home for the summer holidays. She's telling them about this Muggle she met on her walk the other day.
Delilah sighed. "He's so annoying."
Dudley asked, "If this Fraser is as annoying as you keep saying, then why can't you stop talking about him?"
Delilah said, "You asked if anything interesting has ever happened on my walks, dad."
Piers replied, "He did, but from what you've told us, I'd say that you like this guy."
Delilah rolled her eyes. "I do not like Fraser in that way, dad. We just met for God's sake."
Dudley laughed. "Isn't that how it always is in the movies, Del?"
Delilah scowled. "I'm not the lead in some sappy romantic comedy, real life isn't anything like movies. Mark taught me that."
Piers frowned. "Sorry, we were only trying to help."
Delilah told them, "Well, I'd appreciate it if you didn't interfere in my romantic relationships or lack thereof, dads."