Hi Chris- it can be a little tricky as a) a caution has likely been put on your house to stop you from selling it without your Supervisor finding out and b) the equity will be due into the IVA estate anyway. However.... You could offer to voluntarily sell the house in f&f settlement of the IVA on the assumption you would not be able to remortgage at the end of the term in the normal course of the IVA. Think carefully about this however because I suspect part of the reason you entered in to your IVA was to keep your house and if you sell it you will be at the bottom of the property ladder again and it will be very hard to get back on it. Our of interest how many years do you have left and what payments do you currently make? Do you have and friends or family that could 'gift' you a lump sum as an alternative settlement?
If there is equity in the property then creditors may ask for most of this but they usually allow enough funds for relocation. If the property is jointly owned and your estranged wife is co-owner then her share could not be touched but regardless make sure and get creditor approval befor eyou actually sell.
If you could raise a lump sum of £4,500-5,000 this would likely close the IVA down and you could then sell afterwards so benefitting from more equity but this may not be too easy. Borrowing from family or friends would be cheapest but a secured loan could also be an option which could be then repaid from the sale proceeds.
I don't know what your equity position is but it would seem a shame to sell your house for the sake of the remaining £3,600 contributions (excluding any extension for the equity)