That's only in the UK where the children's hospital has perpetual copyright to the first peter pan book/play (I'm not sure about the other works in the series).

That's only in the UK where the children's hospital has perpetual copyright to the first peter pan book/play (I'm not sure about the other works in the series). Outside of the UK it is no longer under copyright. Performances/etc. of it in the UK require royalty payments to the children's hospital. Presumably performances/etc. of derivative works (such as the Disney film) require the same. The same applies to the King James Bible where the UK Crown (and Cambridge Press) hold the copyright to it, where you can't publish that text without permission.