These people make their money out of those who - like you - are unfortunate enough to have to go bankrupt. You do NOT have to use them. There are free services out there which can do the same thing for you (it is not really complicated). Either go to your local CAB or call CCCS, or find out from your local authority whether there is any other free debt advice service in your area.
Incidentally, is the £1200 just their fee, or does it include the £150 cost for the Court fee and the £450 for the deposit? Even if it includes them, the remaining £600 is a ridiculously large sum to do what is essentially a pretty straightforward task. (It may not seem such to you, but for people who do it as part of their job it really is!)