If you are employed by a company they take on the liability of what you do, so you would be allowed to deal with the companies Tax affairs. This is because you are not doing it as a practicing accountant, but as the employee of the company.  But the interview should be for an employed position not for you to freelance.  Then you would be right.

Personally although I could do all of it, when I worked for companies as an employee I used to refuse to do it as I felt they were just using me to get "cheap advice". I once made a suggestion and the MD asked his external accountant for the advice about the suggestion. A week later he got a letter with a £800 bill. He gave me the letter and told me that there was nothing in it, that I hadn't explained to him.