I have drafted a customised General Ledger report to include the opening balance however the opening balances are not showing. Any answers as to why?

You'll want to ensure that the report's date range includes the transactions that created the opening balance, clydeh.

In QuickBooks Online (QBO), the opening balance for a specific period is the sum of all your prior transactions. If your report's From date is set to a day after the opening balance transaction was recorded, it won't be included.  

To fix this, you need to set the report's From date to a day on or before the first transaction in the account. For example, if you started using QuickBooks on January 1, 2025, and entered an opening balance on that day, your report's date range must start on or before January 1, 2025, to show that balance.

If the dates are accurate and the issue persists, I suggest refreshing the browser you're using, logging out, and then logging back in to your account. It refreshes the account connection and resolves issues that occurred in your last session.
 
We've got your back if you have more questions about managing your reports in QBO. We're always available to help you out, clydeh.