SIC Codes missing

Company FC036181 (and others) don’t have any sic codes attached.
From what I understand sic codes are mandatory but I’m not sure if that’s for business types like Overseas company as well.

Does anyone have any information on this?

SIC codes are mandatory when forming a UK Company (and LLP I think), but not all companies on the register are UK Companies and bound by the same laws and regulations. You can usually tell by the two letter prefix at the start of the company number.

In this case FC = Foreign Company, which has a lot less information stored about it (and as you discovered, no SIC codes!)