Can you access batch invoicing without the really expensive advanced subscription?

Yes, Qcontroltuition. You can access the batch invoicing feature with your current QuickBooks subscription plan. I'll explain it further.
 

Please know that you'll be able to manage batch invoices  efficiently in your QuickBooks Sole Trader. However, you will have limited options compared to the higher version.

You can utilize Batch actions to send invoices to your customers and to batch print invoices. This ensures that you can manage multiple invoices efficiently, even within the QuickBooks Sole Trader plan.

Here's how you can access it:
 

1. Navigate to the Get Paid menu and select Invoices.
2. Choose the transactions you want to send or print.
   
   
    
3. Then click Send or Print from the Batch Actions drop-down.
   
   
    

Moreover, for future references you can check these articles to learn more managing your invoices in QB Sole Trader:
 

• Customise invoices, estimates, and sales receipts in QuickBooks
• Create an estimate, and convert it to an invoice in QuickBooks
• Create and send an invoice in QuickBooks

Visit us again if you have other concerns about managing your sales transaction or other QuickBooks related questions, Qcontroltuition. We're always here to help.