The withheld money in its own right won't affect your IR35 status.
It could be argued that you are accepting a financial risk, but I'm not sure that...
you think agencies are bad? Wait till you have to deal with HR instead.... And a HR bod getting paid on the back of your efforts. And who also knows...
When you can find your own work you won't need them. The fact that you use them means that you need them.
In my experience many clients consider the...