As you are less than one month in arrears it seems to me to be very harsh that they would fail the IVA for that reason, without giving you time to catch up.
You say they have asked you to catch up in the next 6 months.. Do you not feel this is unrealistic, you may want to suggest that they allow you twelve months to catch up on payments.
Have you spoken to the IP directly or one of there staff ?
The problem with big companies like BE is the line of communication, the IP is best person to speak with, and you may be better contacting them directly, you should be able to find there email address using the link below if you cannot contact by phone
http://www.insolvency-service.co.uk/newipsearch.htm