You don't need any 'companies' to assist you - in fact, avoid them where you can. Don't shell out any more money for so-called 'advice'.
In the first instance, go to your local CAB, they will advise you. You need to present yourself to the County Court to obtain all the application papers. If you need any help with the papers, once again your CAB should be able to help you. You will have to pay a fee to declare yourself bankrupt - unfortunately this is quite steep - around the £600+ plus mark. You will then be appointed an Official Receiver. He will advise you from then on - don't worry, a lot of this is done by telephone unless your case is particularly complicated.
Also, don't be intimidated or frightened of the whole process. BR is very common, courts are extremely busy, and you may find them surprisingly helpful & friendly - they certainly won't (shouldn't) be judgemental.
You are allowed a basic bank account - but no cheque book. I advise the Co-op who are very good in these circumstances.
It shouldn't affect your job unless you are in finance, such as an accountant. Or if you are in the police or armed forces. Or a company director. Which I suspect you aren't?