If the IVA is rejected, do I still owe you anything ?

No.  If this happens, and it happens in less than 10% of cases, then I won't ask you for any more money.

I only take on cases where I think there is a good chance of the creditors approving the proposal, so I am willing to take the risk of rejection and not wholly covering my fee for the initial work undertaken.

No initial deposit would be required from you for me to commence work on your behalf.  However, I would ask you to immediately cease making payments to your creditors so that the proposed monthly contributions can be made to my client account instead.  Such money is held separately from my firm's own funds and is subject to Client account rules set by the Institute of Chartered Accountants in England and Wales.

Creditors will usually accept a 2 month cessation of payments if they can see that an IVA proposal is being prepared.

As it is likely to take some 1 1/2 - 2 months to carry out the initial work up to the date the proposal is considered at the creditors' meeting I would retain any monthly payments made until that date in partial settlement of my fees, but no further fee would be payable.