Cyprus is an island. That changes a lot of the dynamics. Also Cyprus has the support of its big brother Greece, which the Greek majority Cypriots wanted to unite with. Sudan had no such partner, because the Egyptian rulers aligned themselves with the British.

I hope you can see that Greece is the key differentiating factor here. Any other argument is disingenuous. Not to mention the racist attitudes of the British empire, that saw Greek Cypriots as a "civilized" nation compared to Sudan.