I don't see no reason why the bank couldn't change the terms if they are reviewing the agreement. You are the debtor after all!!.
- Is the bank Abbey National (Santander) by any chance!?
- Contact the credit collection company (if not already done so) and see if you can maintain the current terms, I don't see no reason for them changing the terms if you haven't defaulted with payments and I would think the amount of years that you've been continually repaying the agreed amount of money would be in your favour if you did need it to be.
Good luck with this
:)