Hi laura and welcome to the forum
If your car is being purchased through a hire purchase agreement, then this gives the lender proprietory rights to repossess the vehicle in the event of non-payment. So you would need to continue to make those payments as an essential expense within your IVA.
If the car was bought with the assistance of an unsecured loan, then you would need to include this debt if your were proposing an IVA. Incidentally, an IVA is unlikely to be possible if you only have three creditors.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk