I’m trying to set up my business bank account Santander to QuickBooks when I add Santander as bank it only picks up my personal accounts

Hi there, @bmlbrickwork. 

Thank you for reaching out to the Community. There are some reasons why it only shows up a personal account, it could be you didn't set up yet your business account, in the chart of account and also it could be that your business bank is under sub-account in your account. (which is your parent account and 1st account is with Santander). 

Here's how to create a business account to your chart of account: 

1. Click the Gear icon, then choose the Chart of accounts. 
2. Tap New. 
3. Pop up message will appear, fill up all the field information 
4. Press Save and Close. 

Though, we can use the bank's URL for the business account to connect with QuickBooks.  

For more detailed on how to add an account to your chart of account you can check this article:

 Add an account to your chart of accounts in QuickBooks Online. 

If you have any more concerns about your banking, please do not hesitate to contact us again. Have a great day!