I would advise that you are up front at the interview and state that you are currently off sick and advise the reasons for this. If you have effectively whistle blown then you can use this to your advantage and highlight the Francis report recommendations.
It may be worth you speaking to a senior manager not involved in the grievance to ask about a reference and who this should be addressed to and ask for assurances that this will be factual.
You are probably able to self refer to Occupational Health and so you could do that if you feel it would be beneficial to have it in black and white why you are currently off work.
An alternative to being off sick is to advise that you are happy to work in another environment and seek a short term move to another team. Again this is where speaking to a senior manager would be good about the options of doing this and seeking the approval for this from your GP and OH.
I did this, kind of. I applied for an internal post while I was off due to bullying and went for the interview on my second day back. They asked me about it during the interview so I explained what had happened, what I had done to address it and why I had been off. They asked what I would do if it started to happen again and I had a robust answer prepared.
I would say bring it up at the interview. That way, you have an opportunity to 'set out your stall' as it were - to explain the situation, have a discussion and hopefully mitigate any concerns they might have at this news. If they find out post interview, you may have no opportunity to respond or influence their decision in any shape or form.
I am also a nurse and understand how awful you must be feeling. You could try talking to human resources about being relocated. This should be possible, especially if you also go and see occupational health and talk to them, they will be able to support your case for being moved to a new ward or area.