Hi johnmc
You will need to put your offer to your IP, but it does not look unreasonable to me. If the money is being given to you by way of an interest free loan, then your disposable income you are currently offering creditors may well be used to fund the loan repayments with your creditors approval.
And just to confirm that the Student Loan company are bound by the terms of your arrangement, so when your Supervisor does eventually effect a distribution to them this will be taken into account if they have not refunded the money by then. Get your Supervisor to chase this up as you must be struggling to maintain payments with that deduction coming straight out of your salary.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk