We can investigate this together what's causing the deposits not showing in the reconcile and register page, Brum.
Let's make sure you choose the correct bank account when recording a deposit in QuickBooks. Then, ensure you choose the correct Statement Date period in Begin Reconciliation window . If the deposits are already reconciled, then it will not show in your Reconciliation window.
To trace the missing deposits, you can use the Find tool in QuickBooks.
If the missing transactions are showing in the Find window, you can run the Verify and Rebuild Data utility. It's possible there's a damaged data in the company file preventing the deposits to reflect in the reconcile and register page.
If the same thing happens, I'd suggest contacting our Customer Support Team. They'll investigate what's causing this issue.
Please reply to this thread if you need anything else with deposits. I'm here to help.