And we've only the records left intact by the H7 and his people to tell us of the boys and when they were seen last.
Nope, there were contemporary records in 1483 believing they were dead. And those records were not all English, some were foreign too. And it existed in 1483 and 1484.
There was an uprising in the Prince's favor in September 1483! After Titulus Regulus was passed! Shows how effective that piece of paper was of securing Richard III's rule. And later on that same year, almost all who participated in the rising switched their support to Henry Tudor as king! Why would they do that if they thought that Edward V was dead? Most of them were Yorkists who were loyal to Edward IV! Why would they support Henry Tudor if they think Edward V was alive?
The fact is, Richard III never once produced the Princes in public in after they were deposed. They just disappeared in 1483.
Why not scotch any rumors that he killed them by producing them in public? Remember the rising of Lambert Simnel who pretended to be the Earl of Warwick? That was easily scotched by Henry VII producing the real Earl of Warwich!
Richard III never once did so. He knew there were rumors that he killed his nephews as early as 1483. He did not do anything to counter those rumors.