Some of my already catagorized bank transactions have come back into the review column, when I catagorize them again they double up.

You'll have to exclude these transactions as they could be duplicates, Stopleakroofing.

When handling bank discrepancies in your file, it’s best to have your financial statement on hand before you proceed. As QuickBooks downloads transactions to the For Review tab, these entries could be duplicates if they have been imported again or if other users have manually entered the same entry into your account.

To verify them, you can check your audit logs to see who created the transaction and when it was made.

Since duplicate entries were already categorised again causing imbalances to your account, you'll need to Undo the transaction from the Categorised tab.

1. In the left menu, go to Transactions and click Banking. 
2. From the Categorised tab, select the checkboxes of the transactions that are showing duplicates.
3. Hit the Undo button.

Once done, the transaction will go back to the For Review tab. To avoid confusion when reviewing your data in the future, you can exclude what we have undone. To do this:

1. Navigate to Transactions and select Bank Transactions.
2. Choose the affected bank account and tick the duplicate transactions under the For Review tab.
3. Then, click Exclude.

Once everything looks good, you can start reconciling your accounts to ensure they always match your bank and credit card statements.

I'll leave this thread available for any additional queries.