Hi Gavin and welcome to the forum
The issue about employability in your industry is, I think, largely governed under strict rulings insisted on by the FSA. You may not, therefore, be able to operate in the position you would like until the IVA has successfully concluded, and is removed from your credit file.
With regard to your current non-affordability of the IVA contributions, I would suggest that if you can afford to pay something, then this is better than paying nothing - however as soon as you reach the point of the equivalent of three months arrears, then the IVA will likely fall into default - although given that you are in the final year, this is unlikely to result in overall failure.
Regards, Melanie Giles, Insolvency Practitioner