Thanks for your input. I bought it new for less than £7 (including P&P) so I'll give it a fair chance.
I'll have to set my smart bulbs to something more comfortable for reading lol.
The second problem with Cursed Child (apart from lack of depth, and, I'm also unsure about the narrative vehicle - a play - for the telling of this story) is that of many sequels - which is why many writers - (and, indeed, movies) after some success find themselves seeking narrative refuge in prequels, (and yes, the Harry Potter universe is by no means the only offender, - Star Wars, TLOTR, - I'm also looking at you), a trend I deplore:
Namely: If you defeat and kill your primary antagonist in the original story, - a story with a "save the world" dynamic, where, with the end, you (and your immediate friends, colleagues, supporters) have indeed saved the world and killed or vanquished whatever or whoever was threatening it - what is there to tell, who is there to fight, and how do you develop narrative tension - and, indeed, the narrative arc of your characters - when you return to your desk, computer, camera to tell a subsequent tale with the same characters?
This often means that such antagonists - those in a sequel - cannot carry - precisely because they lack the narrative heft and cannot pose the same threat - the freight and weight of the story in the manner of their murderous, gloriously wicked and utterly villanous predecessors.
Now, there is a very good - and extraordinarily interesting - story to be told about what happens to families, and relationships within those families (especially some of the more prominent families) of both the victors and the vanquished, when the war is over, won and done, (Gitta Sereny's brilliant biography of Albert Speer touches on some of this sort of stuff), and I wish that Cursed Child had chosen to explore this angle, or perspective, further, but - and here's the rub - that is not what those who read something called Harry Potter really want to read.
So, the narrative architecture of the Harry Potter world or universe - that irresistible intertwining of three principal (and eternally popular) narrative strands - in the HP 1-7 books (and movies) - a bildungsroman (coming of age story), a school series, and a save the world epic, which drove the story and offered texture, complexity and context re the world of the story - are all more or less entirely absent from Cursed Child.
Personally - but this is an entirely subjective opinion - I think that this is why the HP universe has since focussed on prequels, because this allows them explore the characters of both Voldemort and - above all - Grindelwald in greater detail, antagonists who can carry the narrative weight of such a story.
