mas wrote:
don't bother with a business account for now - you can use a personal account as a self employed person as all cheques etc. will be in your name - its just a good idea to keep a separate account so you can keep track of income & expenditure when you need to do your self assessment (+ to check you're making money!)
Here here - don't bother unless the bank complains. Also remember you have to register with IR within 3 months of starting business or could be fined.
As for NI you can get a form if have main job as well to declare that your earnings (ie net profit before tax) will be below certain defined level and won't be paying NI. Quite easy to do really. Check out IR website. Loads of info.
Good luck. I don't do web dev. but have p/t business. V hard work