@BasiliskStare with great respect to your learned friend, the IP lawyer, I have it on very good authority that counsel has been consulted on the matter of plagiarism. Yes indeed, David Sherborne QC has once again been engaged and has advised on the deployment of a little known common law action, precedent for which was set in the case of Dusty Bin v Ted Rogers [1978]. Let me explain (with apologies to anyone under 45 who will have no idea).
The judgement in that case resulted in what is called a 321 Order. A 321 Order is named after the format of the eponymous gameshow, and allows a claimant to make great - if not giant - leaps in logic, drawing conclusions which bear little or no resemblance to the base information or clue. It is a legal process that baffles most minds that function on simple logic and reason. It is a particularly useful order for those who are desperate to win a caravan whose brains work in the manner of entitled, delusional princes. Thus, for example, one's gurning, princely chops once again appearing in the Sun is not a result of one spilling out of The Cuckoo Club at 3am, several sheets to the wind, in front of assembled press. No, to deploy 321 logic, it is a result of one's step mother being a frightful old hag and teller of tales to tabloid journos.
And thus we make our first Prince-Potter logical leap: The Leaky Cauldron. Described by the defendant, JK Rowling thus:
Harry ate breakfast each morning in the Leaky Cauldron, where he liked watching the other guests: funny little witches from the country, up for a day’s shopping; venerable-looking wizards arguing over the latest article in Transfiguration Today; wild-looking warlocks; raucous dwarfs; and once, what looked suspiciously like a hag, who ordered a plate of raw liver from behind a thick woollen balaclava."
Clearly this description is based on breakfast at Balmoral. For witches, substitute Harry's aunts and sister in law, Stepford Wives all who think about nothing humanitarian or elevating, they just want to shop on the taxpayer's credit card; for wizards, substitute his uncles, poring over the morning's tabloids trying to find stories about themselves and brag who has the most column inches; the warlocks are clearly Charles and William, both of them violent thugs; and the dwarfs the badly behaved Wessex and Cambridge children. The balaclava'd hag is Camilla, just in from feeding someone to the wolves seeing to the horses. All of them are waiting for Harry to finish his measly portion of sausages and leave the table, so they can start plotting about what stories about him they will leak to the press. Thus, Balmoral at breakfast is The Leaky Cauldron.
Other giant leaps of logic connecting Prince and Potter can be made. Voldemort from the Potter books was once known as Tom Riddle. As the original defendant in the precedent case, Ted Rogers, would have said, Riddle rhymes with diddle. To diddle means to cheat, swindle and deprive. Who deprived Harry of the sausages? The answer is William! Sorry, you didn't get the answer from the clue, and you don't go home with the caravan, have this Dusty Bin toy instead.
Harry's Quidditch and life nemesis is Draco Malfoy, who is blond and horrid and an accomplished pilot. "Mal" means wrongful and "foy" is Scottish for "feast". Clearly this name refers to a wrongful feast of sausages. Draco is an anagram for "A dorc", which sounds like the pejorative noun "dork" meaning a contemptible person. Draco is undoubtedly meant to be William. In fact, many of the baddies in Harry Potter are based on the original depiction of William in Spare, the Crayon Years.
@BasiliskStare you have already pointed out that Quidditch is an aerial facsimile of polo, and that the ginger golden snitch (the embodiment of Harry's character) is to be prized and to be admired. You are thinking the right - indeed, the 321 - way to be included on Harry's legal team. Brava!