sort of feel at the end of my road with working for other people
Will it be so very different working for clients, than working within a management structure ? I've done both sides, and am now very happy to put up with the lesser parts of corporate life for the steady income and benefits which include health insurance, sick pay, paid parental leave.
It's not glamorous but it pays the bills. Don't get me wrong. I love my real work and just put up with around ten or twenty percent which is good enough odds got me.
I'd encourage you to start with a fully costed business plan, covering what business you will need to bring and and how you will do that (and how cover your costs while doing it)
Give yourself an idea of what level of business you will need to generate initially, and then quarterly, annually. Think quite honestly about how good you are at all the other parts of business, other than marketing.
Selling, actually getting the business not just one off but continuing, finance, it etc.
What is your competitive advantage and how do your protect it from others, to ensure you can maintain your competitive advantage over your competitors.
What are your risks and how do you mitigate them. What happens if you loose a few clients, or do not generate repeat business. I'll health, your DC, DH or yourself.
It's not popular to say out loud, but corporate life can be quite comfortable and well rewarded.