The UK was not always sure about the titles of the Malvinas. There are some interesting words expressed by the British Prime Minister, the Duke of Wellington in 1829:

“It is not clear to me that we have ever possessed the sovereignty of all these Islands. The Convention [of 1771] certainly goes no further than to restore to us Port Egmont, which we abandoned nearly sixty years ago. […] I confess that I should doubt
the expediency of now taking possession of them. We have possession of nearly every valuable post and colony in the world, and I confess that I am anxious to avoid exciting the attention and jealousy of other Powers by extending our possessions and setting the example of the gratification of a desire to seize upon new territories. But in this case, in which our right to possess more than Port Egmont is disputed, and at least doubtful, it is
very desirable to avoid such acts.”

Source: Letter from the Duke of Wellington to Sir George Murray (Foreign Office), in WELLESLEY, Arthur Richard, 2nd Duke of Wellington (Ed.), Dispatches, correspondences and memoranda of fi eld marshal Arthur Duke of Wellington, vol. VI, New York, Kraus Reprint Co, 1973, pp. 48-49.