The quick answer
Creditors have various rights. One is to be kept informed so they should receive reports on the progress of the liquidation or bankruptcy. This should be at least annually.
The second is to be paid back some or all of the money they are owed if sufficient assets are realised in the insolvent estate. To be make a claim in an insolvency you will need to complete a proof of debt form.
The third is to be able to challenge fees and expenses of the insolvency. This also includes the right that if enough creditors want a meeting to be held to be able to call a meeting. At this meeting the Liquidator or Trustee in Bankruptcy should answer reasonable questions.
In more detail
As a creditor your number one objective should be to get your money back.
If you are unhappy with the way the insolvency is being administered you can (if you and your associates hold 25% of the claims by value) request a meeting to remove a liquidator.
You also have the right to challenge any fees and this should be stated in any reports from the Liquidator or Trustee on how to do this. It is also worth reading Statement of Insolvency Practice 9 (also know as SIP 9) titled “Payments to Insolvency Office Holders and their Associates” as this set out more information. You can find a copy of SIP 9 on the www.ICAEW.com website.