Are you absolutely sure an IVA is the right solution for you - I am not sure it would be one I would recommend, given that you have debts of only £23,000, equity of £16,000 and presumably the ability to fund ongoing contributions.
Although Northern Rock are now accepting more IVAs, they are also very careful scrutinisers of your statement of affairs which may indicate that if you were to pay contributions and also sell your property, you could probably afford to repay them in full over a much shorter period than you are proposing in the IVA.
Sorry to raise this issue - but I am suprised that your IP has not. A debt management plan may be a better option and should certainly be considered as a fallback in the event that creditors reject your proposals.
Regards, Melanie Giles, Insolvency Practitioner