Assuming you’re looking at an officer item or the officers list then the key field is the
officer_role. You’ll see in the documentation (You can also see a list of these in the “enum constants”) that this can contain a range of values, some of which are the same except for “corporate” e.g.:
Those starting with “corporate” are corporate entities. There may be some other differences also e.g. comporate entities may have a
identification member with details about the company / entity, while “natural persons” may have
surname members. In general do not rely on these appearing and check / validate any values you do find there! Companies House dataset is essentially one that the public fill in themselves…
There is a similar but not identical system for PSCs / RLEs and Legal Persons. In the PSC list resource the
kind field conveys “what this is”. The start of this string is one of “individual”, “corporate-entity”, “legal-person” or “super-secure”. The last means “there is one but we are not giving any more information”. These strings then end in either “-person-with-significant-control” or “-beneficial-owner” - so 8 possibilities.
Your second question - I’m not aware of any consistent way of marking the CEO in the data. The CEO would normally be expected to be a company director. However I believe this is not necessarily a legal requirement. Consult the relevant companies law on this, I am not a lawyer!