You're always told the monarch has only symbolic power, not power to over ride Parliament. Last time that happened the monarchs head say goodbye to its body.
The Guardian story does a (deliberately?) poor job of pointing out that despite these revelations, the symbolic nature of it may still very well be the case.
ie that nothing in the document excludes the idea that just like certain other functions and powers that the royals still have according to the rules, the decision made by the royal is not in practice their decision, because it would cause a crisis if they actually tried to make their own decision rather than doing what the government tells them.
In this case, the idea that they only refuse consent if ministers tell them to. Theoretical power vs the ability to actually use a power in practice without unthinkable consequence.
Personally I think that if you are going to have a state with a detailed structure laid out, you should really try not to have it cluttered up with historical quirks or dead ideals about where power lies, no matter if they are mere formalities. Even if its not the royals who may on occasion still be able to make use of the power, someone else might be able to in order to exert their political will by playing procedural games. And it can look bad and suspicious even if there isnt really much going on. A fair and transparent system should leave no room for people to even have to wonder whether the tail is wagging the dog or the other way round, or have to rely on an absence of detailed and specific revelations in order to be vaguely reassured that nothing too dodgy is occurring.
The revelations of the last year or so have been rather interesting, but no smoking guns that cause me to attribute more power to the royals than I already thought they had, just a fresh demonstration of why the old relics may yet have side-effects that are worth complaining about. Absent some actual revelations about how any of the consent refusal decisions were actually reached, the Price Charles lobbying stuff was of more obvious interest to me as that demonstrates a channel of potential influence that is a bit different to some rubber-stamping. But the release of that stuff was blocked. And I may have this attitude because I wasnt exactly buying the idea that the royal household was utterly impotent on every front in the first place, anymore than I am willing to jump to completely the opposite extreme now.
Aside from the numerous features of this parliamentary democracy which are well-deserving of being considered a laughing stock when explored in depth, for example some of the failures to properly separate legislative, executive & judicial branches (some of which we finally got round to tinkering with this century), much of the action, the power & influence, can be found by looking at who owns what. So I'm still more inclined to point at the property etc portfolios of certain members of the royal household when I want to shout loudly about the power and influence of the royals and their willingness to use it. That and the symbolism of having royalty at all, which sucks for a number of reasons I doubt I need to mention.