I set up a limited company from the start, mainly as my vision was always to grow a company which employed staff down the line and I felt it was the best structure to do that in. I am not sure there are many tax benefits till you would be getting charged 40% tax if you were self-employed. At that stage you would be mad not to convert over to a limited company as your tax liability would be 20% normally.
If you are looking at it primarily from a tax avoidance perspective it's not worth bothering with until that point.
As far as I am aware, setting up a Limited company doesn't protect the name, only that name with Limited or Ltd after it. Nothing at all to stop someone setting up a Sole Trader company called Dripbusters for example. Now if they use our logo that's another thing, as it's copyrighted.