Martin50
Some people might disagree but I don't think you need to cover every conceivable topic which affects the retail sector. If you haven't worked in the retail sector before, the interviewers wouldn't expect you to do so - their main aim is to gauge/assess what transferable abilities, knowledge and experience, etc (e.g. initiative, ability to work unsupervised and/or in a team) you've already got in comparison with the other interviewees, and then select whoever they think is best suited to the job in their organisation. The fact that you've been selected for interview out of probably many applicants is a positive one: The organisation will have looked through the various application forms it has received and decided from the information on yours that you're worth interviewing. Also, though I've no experience of the retail sector, the topics you've listed strike me as being fairly comprehensive. As a major retail organisation, it's very likely that the company already employs a number of experienced OS&H people and that one or more of them will be involved in the selection process including the interview.
For you and anyone else facing job interviews, another general slice of advice is to bear in mind that while the prospective employer organisation is assessing you as a potential employee, you in return will tend, consciously or otherwise, to be assessing it as a potential employer in various ways. These could include the individuals you are likely to be working for and/or with, plus slightly less tangible aspects such as its safety culture. Therefore, if the selection process doesn't already include an informal opportunity to meet potential colleagues, it might well be appropriate during your interview to ask if this would be feasible at some stage. Ultimately, if you are offered the job, you will know, partly from 'gut feeling', whether to accept it or even say no. After all, though you'll have gone through one or more formal/semi-formal verbal interview procedures, the whole recruitment process can and should be thought of as an interview during which you and the potential employer weigh each other up!
Depending on their circumstances, especially at times when good jobs are hard to get, job candidates who don't relish what they find out about the their prospective roles and employers, might think it appropriate to accept unrelished jobs in order to earn a living and keep gaining experience until they can get what they regard as better/more desirable jobs.
p.s. I had intended to post this response earlier this week but was delayed by the fact that my usually reliable internet access stopped working for some unknown reason on Tuesday evening, worked very sporadically yesterday and resumed several hours ago. Therefore, Martin, I hope the interview goes or went well for you.
Another thought - If you don't get offered the job, perhaps it and the organisation weren't really for you. If so, the interview and other aspects like deciding what to include on your application form will still have comprised useful experience as regards future interviews and applications. Also, some organisations are willing to give constructive feedback after interviews to those who were not offered the jobs involved.
It's not unknown for a chosen candidate to decline a job offer and for some time to elapse, e.g. because of holidays, before the job can be offered to the second choice of candidate. Also, in circumstances where someone starts a job and decides to leave soon afterwards, the employer might well decide to contact the next best recent interviewee/s to ask if they would still be interested in the job.