Hi there blueleon and welcome to the forum
Could you firstly let us know how much you owe to the Student Loans Company - as they can be a tricky creditor in IVA proceedings.
You should not have to pay anyone any money up front to propose an IVA for you, but the insolvency practitioner will have costs which will have to be paid from the monies you introduce into the arrangement. These will be tailored to your particular case, but a nominee's fee is usually on average £1,750 and supervisory fees are generally chargeable at 15% of realisations received after the nominee's fee has been paid.
I cannot recommend a specific company to you, as I am an insolvency practitioner myself and we are not allowed to promote our services on the site, but you may like to take a look at
www.iva.com - an IP firm comparison site - which will give you client feedback which ought to indicate how well a firm or an individual IP is performing.
An IVA really should only be proposed if you have regular income with which to fund regular repayments, but don't let this put you off as anything is possible. I suggest that you have a chat with an IP to see what options there are available to you to deal with your current indebtedness - and well done to you for addressing this before it gets too serious.