Ltd company - bunch of questions?

It really depends where your company is based because if im not mistaken Jersey or one of the channel islands are exempt from paye tax and N.I, I have come across a few false hopes companies which promise temp workers the world, but there are loads of hidden charges etc. like emplyers N.I and Employees N.I which they pay, but all they say is that they pay something like �15 admin charges a week. so be very carfeful who handles your money before you do.