In reply to Taurig:
Not in your field, but I do a lot of contracting in the IT field. As a few people above have said, setting up a ltd company should cost you little (less than £100, plenty on the web), most of the other stuff you've mentioned seems just regular tbh.
The one thing to bear in mind, is that the figure you are getting paid, is not actually your's, but goes to your company. Generally you should be able to get a large % of it, but some goes on things like company TAX/NI/Accountant fees etc, so you won't see it all.
I've never worked under an umbrella co. They take some of the hassle out, but it's not difficult. In my view you're just paying them to do something you could easily do yourself.
Get your own accountant though, that really is too much hassle to sort yourself. Allow £1,000 per year as a rough guide for this.
A lot of companies want you to have personal indemnity and public liability insurance, cost varies but probably something like £100 per year for each.
Honest, it really isn't as difficult as it seems.