I've been in an iva since 2018 and just got car insurance since then. It's been just over a month and they've give me notice of cancellation due to unsuccessful credit application and can no longer offer monthly payments. With them cancelling it, the premiums have shot up even more and I'm stressing out. It says nothing in their terms on conditions and I even spoke to them a couple of weeks ago to confirm the date the money would be took and they mentioned nothing.
Some insurance firms fund monthly payment contracts with a loan upfront --- it would appear that their loan company isn't happy with your credit score. You will need to find an insurance company that self funds monthly plans, or pay the years premium in advance, or find one whose loan company isn't too fussed.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk