Do you have to have answers to the questions you ask of others?
If so, I don't think it's any use asking us because you need to ask about things you are passionate about.
I think personally I would focus on the key things that are blighting the country currently: workforce shortages (impacting everywhere, but specifically farming, education and health/social care), the concomitant slow-mo disaster that are health & social care and education - including but not limited to workforce, waiting lists, quality of care, buildings/estates, workload.
But those are my areas of interest - I could bore someone for hours on any of the topics so I am confident I would be able to make any required response suitably erudite.
So e.g. my question might be "There is a shortage of staff for the health and social care workforce now. This necessarily limits our capacity to train staff as a result of the shortages, and in any case even if we started training more staff now, doctors wouldn't even enter their F1 year for 5 years. The government has promised to bring down immigration which limits the capacity to open our borders to qualified clinical staff. Given all of the above, how would you solve the current shortage of NHS staff, which is resulting in burnout for the staff, poor retention for the trusts, and an NHS on its knees that isn't meeting the public's needs?"
In reality I'd probably get told that was too long, but I think it's important to answer all the common arguments before you ask them a question.