Too bad there are a lot of records missing.
But a "lot of records" still exist, including contemporary signed documents of Henry Sinclair, as you have mentioned on these threads of seeing his signature.
With that premised, there are NO Medieval contemporary documents that mention a Sinclair voyage to the New World, nor mention that Sinclair was absent from his homeland during the time of the alleged voyage.
The very first mention of this alleged voyage was in 1875, when Richard Henry Major translated the fictional Zeno Manuscript into English and identified "Prince Zichmni" as "Prince Sinclair" without any real basis of proof.
With this translation as he sole evidence of a Sinclair voyage, descendant Thomas Sinclair claimed his ancestor discovered "America"/New World before Columbus, and petitioned the British government to acknowledge this, which they didn't and did not take his claim as legitimate history due to the total lack of collaborating records of this claimed voyage.
Which brings us back to your statement, "Too bad there are a lot of records missing".
While you state there are records missing and that there are NO contemporary Medieval records at all concerning this voyage of Sinclair, you have with several posts on these Oak Island threads presented highly detailed description of events surrounding this alleged Sinclair voyage, some reading like an adventure.
If the first mention of this Sinclair voyage was in 1875, 400 years after the alleged event, with no Medieval contemporary mention at all, and if, as you stated about a missing records:
What is the source of the highly detailed information that you have posted about this Henry Sinclair voyage that is not acknowledged by the professional academic community of scholars due to the absence of actual documentation of this voyage?