If a new expense transaction relates to a previous supplier the system automatically adds to a list and defaults to the latest date. This does not make sense to me

Thank you for reaching out to us, @jo-millyincdxb-c.

I'll be glad to help you with your expense concern.

I would advise you to put a checkmark on the downloaded transactions that you would like to edit and then start updating the details.

Creating rules that categorize transactions. The more QuickBooks uses bank rules, the better it gets at categorizing.

Let me share information about Banking Rules:

 Create a bank rule

1. Select Banking menu. 
2. Choose Rules tab New rule.
3. Provide a name in the What do you want to call this rule? area.
4. In the Apply this to transactions that are dropdown, choose Money in, or Money out.
5. In the In dropdown, click the bank or credit card account.
6. Set the rule conditions.The transaction must meet All or Any of the conditions. You can add up to 5 conditions.
7. In the Conditions fields, specify whether the rule applies to Description, Bank text, or Amount. Then select Contains, Doesn't contain or Is exactly to decide how Quickbooks applies the rules.
8. Choose the settings for the rule. Select the Transaction Type, Category, and the Payee to apply.
9. Click Save.

You can also check how to Void or delete transactions in QuickBooks Online for more information about invoices.

We're always here in the Community to help if you have other questions related to QuickBooks. Stay safe!