And one of them is not writing a double review as if it was a single. I dont think that would be right.
Option one is what Julia said. See the one lady (the one that wants the review) again as a single and review that date.
Option two is to write up the double review as a double and leaving one girl anonymous. The profile for doubles is only going to be for one of the ladies anyway. So you write it up and submit under her name. (the one that wants the review, of course) Then, when you write up the body of the review, you only name the one. Let's use Julia as an example since she posted on this thread  You would write it up as "I had a doubles session with Julia and a UTR provider" or "Julia and a provider that wishes to remain anonymous." In describing details you say something like, "while Julia was ... The other lady ..."

I have read a review like that before so I don't think it is against TER policy, and you would be honoring both ladies' wishes.
My.02

write a review and place both names in the nane box, like 'Suzy/Janie'.  this will create a profile for these two girls as a duo.  It will create a profile for them as a double.  It will not appear on their individual profiles.  If you want to do a review of either one by herself, it may not be approved, it you do a review of them together.  With the changes TER has instituted, it's hard to say what will happen.

Swim