My IVA started in January 2006, and I have never been late, or delayed any payments to date. My car has always been outrightly mine, and is a 51 plate peugeot 206. For a long time, it hasn't worked very well, and it fails to ignite, the cambelt, i've been told, will need changing which will set me back around £400. The battery, I have also just replaced with a brand new one, but is still failing to start most of the time. I've weighed up the option of attempting to buy a car on finance. My car would probably only fetch £1500 on part exchange, and I'm hoping that if I can reduce my monthly payments, I would be able to finance a car for around £150-£200 per month.
What are the chances that my IP would approve this, as I do need a car for work, as I have to travel to other business sites. At the moment, I pay around £350 towards my IVA. If I can propose to get a car that would lower my car tax (to the £35 band) and ultimately cheaper insurance (I have a 1.9 diesel at the moment), I'm confident that that money saved would contribute to finance.
As you say a car is essential for transport to and from work, but you may find that finance payments at the level you are suggesting make the IVA unworkable. It is difficult to advice on your case specifically on the forum, without fuller details of your IVA and current personal circumstances, so I would chat through the options with your own IP for more specific advice on this point.
Hope it all works out for you. Other options could be borrowing money from a family member to purchase a replacement vehicle, or simply trading the car in for a reliable cheaper model.