Ash I've had three calls this week alone asking if I wanted to take on a government funded apprentice. There are ways and means out there for you to educate yourself properly and earn as well. I personally don't think youve bothered to look into it, and what your actually doing is thinking thatbthisnis easy and you're seeing pound signs.
Starting out on your own with little or no experience, and as self employed is going to be hard for you. Especially with no rapport behind you.
You say your going to declare everything? Well lets say for example you do a kitchen splashback back one week. That's all you have on your books that week. Lets also say for arguments sake that that job earns you a top line of £250.00.
Take that and deduct profit tax, NI contributions, fuel, car tax, van insurance, public liability! See what you're left with. I think your a bit blinkered mate and trying to run before you can walk.