Sudden Benefit Review Interview

Hello Everyone,
I am new to the forum and hoping that you can offer some advice with this:
My sister was migrated into the ESA support group last year
we know from her WCA report that she was awarded 18 months in the SG, so her next medical assessment is due in Aug, which we have of course, like everybody else, been hoping will now be deferred.
Now, out of the blue, she has received a letter from the local job centre requesting that she attend for a 'benefit review interview' next week.

I have read all the posts relating to compliance interviews and am now wondering whether this is one. If it were a compliance interview would it necessarily be named as such on the letter, or is a 'benefit review' something different?
It is simply addressed from the ESA section.
The letter gives little other info as to what the interview may be about beyond the standard "this interview has been arranged to ensure you are claiming the right benefit" adding ominously "when you claimed benefit you agreed to tell us immediately if your circumstances changed" ( her circumstances have not changed !)
They have however asked to see any bank statements/financial docs etc.
Am I entitled to ring and ask what the interview is in connection with,and are they likely to give me any info over the phone, given that it is me that will be contacting them and not her?
Which brings me to the next question-

She is in the support group because she has PTSD, anxiety disorder ( and is bi polar) and got through the WCA on paper evidence alone. This included a letter from her doctor explaining that her disability includes a social phobia and therefore any social contact/ interview- type situations etc will exacerbate her medical condition.
I am therefore wondering whether she has to attend the job centre at all, given that she was deemed too unwell to attend the actual medical.
I don't know how much info the job centre staff have about her medical condition.
Now to the crux of the matter:
She won't be able to attend the interview alone and I am the only person who is able to accompany her ( other relatives now living 200 miles away) but I am off on holiday now, so not only can I not make the interview next week, but I won't be able to arrange a further appointment until 10 days beyond that at the earliest.
The letter does ask you to phone if you are unable to keep the appointment but
I am wondering what the DWPs position is on re-arranging appointments etc.

If you cannot attend an appointment are they legally required to send you another before taking any punitive action? And does the re-arranged appointment need to be within a specified time?
Can they impose sanctions on those in the support group?
She is terrified they will just terminate all her benefit immediately if she does not attend.

They have requested that she bring any bank statements etc, which they obviously want to check, but I was wondering if we could post the copies to them as she is concerned about appearing un-cooperative.
I am really unsure how to approach the DWP when I ring them and
I would be really grateful for any advice you could offer.




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Thanks for that Gordon.
We shall have to try to telephone the DWP together as you suggest.
When we do telephone the job centre are they likely to tell us whether it is a compliance interview or not?
Having read all the posts on compliance interviews I am aware that there is also something called a interview under caution.
The last thing either of us want is to get there and discover it is one of these.

I have been wondering as the majority of ESA re rererrals have now been suspended that there is a new tactic to get people of ESA using the compliance interview. I did think this reading the recent news article on this site, News story