You are best getting an accountant to look after the limited company for you due to the complexities involved. As advised above it will more than likely be profitable for you to register for VAT.
You do need an accountant that is familiar with contracting, but you must choose wisely. I have just took on a client who was using a very well know sepcialist contractor accountancy service (it's won awards) and the level of service and advice was shocking...
As Mario has noted, there is the umbrella route. However this may be more costly than your own limited company route as whilst the fees may be lower, the overall tax take is higher. You also have to be careful about the claims that these providers make about deductions as they are definitely 'sailing close to the wind'.
Whether or not you are under IR35 is all down to your contract and what your employer
suggests. It is quite complicated and is always specific to each individual/employer.
I'm happy to discuss further with you if you want to. PM if interested.