Also car insurance (employed or student)

A friend told me to post here.

I'm currently a mature PhD student. My project is industry funded. Next to that I work in my profession as demonstrator or tutor. For this I pay NI and get holiday pay. There might be months where I work 80 hours per month, others with none.

I tried to figure out whether insurances consider me a student or employed. I phoned or chatted with a few but I'm none the wiser. Insurances insist I am employed as long as I earn money but they cannot provide me with further details, if I need to earn money every month, and if there's a minimum. I don't want to end up providing incorrect information and not be insured. Yearly premium difference would be £50-80.