I would be asking what the company could do for you ( i know its NHS, but adapt). If you are already in work, I have never stressed over an interview. You have no real idea who or what theyre after, the job might already be a done deal and the bosses niece has it, and they are just interviewing to make it look less suspicious. This has happened to me in the past, as when I challenged them on my rebuttal, it was evident they hadnt even read my qualifications or experience, just interviewing to follow procedure.
Also, look at who is interviewing you, is it strictly some HR rep, or is your direct future boss present? You re going to be spending a lot of time dealing with them, so you are interviewing them for the role as your boss also.You might not have any confidence in them post- interview.
I would be asking for what promotion routes are available, any perks, holiday entitlement WHEN YOU WANT, etc. You have no control over whether they like you or not, so just be honest and open. If you do well, they will be seeing t he real you soon enough, and if it goes bad, oh well, there are always other roles.
Having said all this, this is advise given having made mistakes in the past. If I had my chance again I would treat the interviews as more of me interviewing them, than me sitting there thinking of the right thing to say to appease them. The best job I ever had was as a eesult of having an awkward argument with the interviewer. You never know what theyre looking for.