Thanks for the replies. I ticked unemployed, but they asked for proof of monthly income. I do actually have this, just not through employment, and I showed them proof. I just don't have what they've requested, though I've already proved I have the 500k plus monthly income and can adequately support myself. Just bureaucratic nonsense that's impossible to navigate.
Thanks for the replies. I did show the 500k, but it's in a different account that I don't use that often. I transferred into it just before I applied, so maybe this is the reason they have asked for extra documents to show that I have had an income for the last 6 months.