@Tom ******
for me I showed my business, I have a website and a company presentation. I actually showed an investment account as meeting the financial requirements (which includes a SIPP), they also asked for some other proof, in my case a tax return (nothing exciting or onerous there). That was roughly it. No insurance requirement, medical requirement etc. I guess that if you established an online presence and showed that you were genuinely freelancing (I explained that I freelance for my own firm) then that would satisfy the requirements. What have you always wished to do? Or maybe you already have a legitimate business. There are other routes under soft power: cookery, language, Muay Thai...