My business partner is in the process of going through a personal Iva. I would like to know if this would affect us as a limited company applying for a business grant in the future.
You need to work out what is needed to ensure that if your business partner is not able to complete the IVA what happens next.
Applying for a business grant is the least of your worries at this stage.
IVA started March 2011, Completed March 2016 and certificate issued 11 days after final payment. It was not always easy but then some of the best decisions aren't.
I assume your business partner is co director and 50% shareholder. You need to check the articles of association to see how the IVA affects the company and any debts of the company personally guaranteed by the directors will now be your sole risk.
You should consider legal advice to protect your own position but your partner did right by letting you know.