To ensure that your cash book and nominal reconcile you do the following: 

To obtain the nominal balance - go into the Nominal Ledger and select Ledger Reports. 

You should always run to the last period of the year, for example, period 12 - this is in case anything has been forward dated. 

When the report has finished, filter for the bank nominal code in question (or for any other bank you are reviewing - as can have multiple cash books). 

Make note of the YTD figure. 

To obtain the cash book balance go into the Cashbook and select Reconcile. 

Make note of the Opening Balance and then tally up the amounts in the Paid In and Paid Out columns. Then add the overall figure to the opening balance. 

Note: if there are multiple transactions on the report - you may find it easier to export to a spreadsheet to report on the In and Out columns.

This balance should match the nominal balance from the Ledger Report (also known as Trial Balance). 

Note: we would recommend to review this each month to ensure that it balances. If it does not balance, it is easier to report back on a single month than it is a large period to identify where an imbalance has come from.