Preparing for an interview

[happywilly]

Just wondering how long you'd normally spend preparing for an interview?

I have an interview in a few days and I expect the following to take me 4 hours or so:
Their vision and values
Their attidtudes to diversity and ethnicity
Research interviewers and organisational structure of the dept
Go through the job description, person specification and behavioural attributes
Revise how do do specific function on word that I haven't done for a while but is mentioned on job description.
Basic understanding of GDPR
Prepare answers to expected and competency based questions
Questions to ask them

Is this too much, too little? Is there anything I've missed? It is for an administrative role at a University.

Thanks