The bank's debenture will usually take priority over most trading debts, so in practice you could be wasting your time.
In a similar position some years ago, I bought goods from the people who owed me money, and argued them into offsetting the transactions.
This could be dangerous if a receiver is called in, as he would almost certainly not agree to this.
If you have supplied goods to them, and can identify them, you may have a lien on them as an unpaid seller of goods.
Take legal advice before doing anything. AB is free, but free advice isn't always the best!