Am I self-employed?

I am assembling the materials for my ILR - SET(M) application.  I have a question about whether my wife's wages should be categorized as employment or self-employment income. 

She works part-time for an editorial office- they do a bunch of behind the scenes work in the scientific publishing process.  Her official title is "freelance editorial assistant."   She's not on any sort of contract, but has agreed to work a set number of hours per week (paid hourly).  They DO NOT take taxes from her income and she has to sort that out herself.  However, she's only been doing this work for about 6 months and hasn't looked into the process for paying those taxes yet.  Side note: We're both foreign born even though I can gain settled status through her, so we're both naive to the UK tax laws, etc.

The criteria on the Home Office form for self-employment requires categorizing this work as either sole traders, partnerships, franchises, or directors/employees of a "specified limited company". The only thing she could be is an employee of a "specified limited company."

The website indicates
a specified limited company is:
-the person is a director or employee of the company; and
-shares are held (directly or indirectly) by the person, their partner or the following family members of the person or their partner, parent, grandparent, child, stepchild, grandchild, brother, sister, uncle, aunt, nephew, niece or first cousin; and
-any remaining shares are held (directly or indirectly) by fewer than five other persons.

My apologies if this is drifting into tax law and not immigration law.
Does this mean she would have to setup a company in order to pay the taxes (which we would then fit the above criteria)?  OR, is she employed by this editorial outfit and just pays taxes on her own (in some way that I haven't looked into yet).

In reading around online the criteria for what constitutes employed and self employed is vague, but the freelance in front of her job title makes me think we need to look into setting up a "company."

Happy to answer follow ups.
Many thanks in advance
M

Do not set up a Limited Company for this situation, I don’t think it’s appropriate. Limited Companies are an entirely different ball of wax and a difficult way to prove the income requirement. My husband is the director of an LTD and it’s been an absolute nightmare getting everything in order to apply for the visa. I’m currently waiting on a decision while pulling my hair out. I’m pretty positive your wife is considered as a straight forward self employed situation by the information that you’ve given. For Self Employed income to be considered you must submit the full 12 months banks statements and corresponding tax year documents completed by an accountant, April to April plus more for proof of ongoing income. 6 months will not be sufficient. I know Category F doesn’t list the term “freelance” but from my understanding, and others I’ve seen apply under Cat F, this sounds like the category you need to use. I’d start by figuring out if this will work for your visa situation and then speaking to a qualified accountant. Be aware that accountants are not familiar with visa requirements so you will need to work with them and the visa guidelines, you may want to consult with an attorney if you’re feeling really stuck. We used Medivisias. Good luck!

Thank you for your input, Calitobrum.  I appreciate it.