Been through this myself and I want to be brutally honest because I don't believe in sugar coating anything. In highsight I wish I had known how things most likely get played out. I was naive at best.
Sorry, this post is lengthly, but I feel it's important so you have the knowledge to make informed decisions.
So, the good news is the interview itself is absolutely fine. You are in a 'safe house' where you can sit comfortably and you can give your version of events. They may ask you some prompts if they feel they need to know anything else, or if they want you to expand on anything. Everything is recorded and you can take breaks if and when needed. It is all relaxed and nothing to worry about. I did feel believed.
Now, the bit which I feel you do need to know (this may be specific to my case, but it is a headups for what may come next).
If your case goes to the CPS, and their action plan is a follow up interview, this will not be pleasant. For me, this was a nasty, calculated cross- examination. The CPS had asked the police to scrutinise my evidence and I broke down as I felt like I was the one on trial. It was the most horrifying, victim- blaming situation I have ever been in. I have needed more therapy for that than the actual rape itself. If you are ever called back for a second interview, please please think carefully and prepare yourself for what they will ask. It will retruamtise you all over again, and I can't let that happen to another woman. Please take your ISVA or someone with you if you want to go ahead. I had nobody as the police failed to tell me. They lied throughout. I walked into the safe house believing I was just having another interview, and that's when they dropped the bomb on me. I felt trapped, but against my better judgement I went ahead with it. It is a decision I bitterly regret.
The KC then decided it was 'my word against his' and NFA my case anyway. They put me through absolute hell to only go and drop my case. And I'm so sorry to tell you that this is the liklihood of yours too.. Unless you have a solid confession, or have significantly strong evidence, they will not charge. I thought I had very strong evidence, so was flawed when they dropped my case.
However, I'm not saying that what you are doing is not the right thing. We must always come forward and report. After I reported, another person came forward a year later. As I'm typing this to you now, he is facing another charging decision for abuse against a minor(s) I believe. Horrible cunt.
The most important thing is, you need to take care of yourself and be kind during this difficult time. Fall back on your friends and family. Get a good ISVA straight away and if you want to talk privately, you can always PM me. X