Creditors Voluntary Liquidation is started by the directors, they tell the shareholders the company is not viable, it is insolvent and they must stop trading.
The shareholders then ask a licensed insolvency practitioner to call a creditors meeting as soon as possible (not less than 14 days notice is required, but its usually 21 or so days).
In a compulsory liquidation, a party lodges a winding up petition with the court to have the insolvent company wound up in order to recover the outstanding debt.
The petitioning party may be a creditor, shareholder, Secretary of State, or an Official Receiver.
I understand that the last people you would ever want to speak to would be a business rescue firm, but I also know that trying to understand your options can be equally challenging.