I am not a lawyer - I'm just offering an opinion based on 20+ years of running a UK Ltd and being a news/research junkie (FT, Bloomberg etc).
I believe you can use a logo so long as you are not implying a relationship exists between the two of you.
My bigger concern is if you write something that is discovered to be false - My understanding is if you were sued, you would have to prove that you published your article in good faith, believing everything you said was true. If you could not prove to the court that you had performed sufficient due diligence, you could be held liable. I presume you are publishing under your own name, and not under an entity (like a Limited Company) thus if you lost, the company could kill your credit history).
If you still want to proceed, make sure the post is dated, make sure you reference the sources of your information where possible. Make sure an opinion is an opinion and not misread as a fact.