#I'm also interested in whether the Masked Singer examples were Harry's recordings

[dogsliampaynedoesntinstagram]

"But the fact that Harry is saying yes to Love Island and no to Hesrtstopper is information." Incorrect information. Harry is not required to give permission for use of his songs on Love Island. Songs appear on Love Island under ITV's blanket synch licence. There's a standard fee for use of about 100 quid per song.

Anon 2: He said yes to love island for the fine line era only. I've watched all seasons of love island uk and nothing from harry's house has ever been played. they played a long excerpt from falling in 2020.

I don't think that's quite true anon 1. Given what you said I googled and found this article, which makes it clear that not all songs are available to the Love Island team:

“I’ve had the perfect song for a synch before,” Schewitz starts, “Then the Love Island team messages us, like, ‘Hey, this is cool and all, but it’s got copyright control showing up on PRS. Then you have to send some emails to artist management with ‘URGENT’ in all caps to contact PRS and amend the registration. We’ve lost opportunities when the artist’s team can’t move fast enough on splits.”

As Anon 2 said it seems as if Harry made his music less available since Harry's House and it has been removed from this sort of licensing. But he is still licensing it out to American comedies such as Platonic and God's Favourite Idiot.

It is a good point that his choice to make his music available for Love Island was earlier than his choice to make his music not available for Heartstopper - but they were both choices.