Harry's schedule for the next week is full, with the sources saying his diary is "packed" with meetings and official engagements – after which he's due to fly back to Canada to reunite with Meghan and their eight-month-old son, Archie Harrison Mountbatten Windsor.
The Daily Mail says this could happen as early as next weekend, and will certainly happen within the next fortnight at the most.
And it seems there's a good chance the family won't be returning to London at all, after royal watchers noted the pair's pet pooches had joined the family in their Christmas getaway to Canada – but had not returned to London with them on January 6.
Meghan's rescue beagle Guy, who she adopted prior to her relationship with Harry, and a black labrador puppy both arrived in Vancouver in November, with royal insiders telling Daily Mail this was "the biggest clue, in hindsight, that they were unlikely to come back from this so-called holiday".
"Both the Duke and Duchess adore their dogs and Guy has already been relocated from Canada to London once when Meghan moved over," the source continued.
"She wouldn't have considered a move again for him if it wasn't going to be at least semi-permanent."
The major clues that the family of three have already started a new life outside the UK come amidst reports the Queen is "deeply upset" about the whole situation.
She was seen looking very stony-faced as she emerged from her royal home in Sandringham wearing a headscarf and a grim expression as she climbed behind the wheel of her Range Rover.
According to UK paper The Mirror, Queen Elizabeth drove a few kilometres down the road before she pulled in to a field where a shoot was taking place. A number of guests – including another of the Queen's grandsons, Peter Phillips – were awaiting her arrival.
"The Queen will be feeling very let down and very angry," the Queen's ex-press spokesman Dickie Arbiter said on TV show Good Morning Britain.
"Probably more angry than she felt after [Prince] Andrew's car-crash interview [regarding his friendship with disgraced financier Jeffrey Epstein]."