Quotes from your own article, which you seem to be unable to understand.
[a] foreign prosecutor can question a suspect in the UK by telephone, videolink, or through British police
Get it?
Through the British Police, ie the British Police are the ones doing the interviewing which is based on questions supplied to them, if you read the MLA this is very clearly spelled out.
If the latter option is used, it is possible for officers from the foreign state to be present during the interview
The MLA shows that this is both a requested position that may be granted or denied, and an observational one. They may be
present, they may not participate.
Then your author throws away her own sources and states...
Ms. Ny had a wide range of options for interrogating Assange in the UK: by telephone, video link or by interviewing him in person, together with British police.
We already know that the Swedish courts say no to telephone and video link, so no she didn't have those options even if the UK allows them. And the author herself just noted what the MLA says, but then amazingly manages to totally reverse what she just said. Ny does not have the option of "interviewing him in person, together with British police" she has the option of the British Police interviewing him in person while if allowed, she watches.
The author is actually quite clever in what she says, and other than the statement that Ny had the option of "interviewing [Assange] in person, together with British police" what she says is true.
1) Ny claimed that she couldn't interview by phone or videolink because it is unacceptable in Swedish Courts. This is true.
2) The UK allows Telephone of Videolink interviews - This is true, but useless since Sweden does not.
3) Ny can be there when the UK Police can do the Interview for her (if allowed to) - True, but she can't take part in it.
4) There is nothing in Swedish law stopping Ny doing an interview in the UK - Again true, it is UK Law that stops her from doing so.
This quick slip step between what UK and Swedish law allows is very fancy, and she hopes that in the middle of it, with a little twisting of the truth by claiming that Ny can be part of the interview rather then just an observer as in the MLA, the author hopes that people will think that Ny is being silly and egotistical for demanding that Assange goes back to Sweden. In reality, the conflict between Swedish and UK laws means that if Ny is to do the interview herself,
it must be done in Sweden. There is no other choice, and even your own author, who tries to avoid that conclusion to the point of twisting her own sources right after quoting them, admits each point with her article (though then dishonestly ignores her own sources and quotes to claim otherwise.)