You can enter the baron and CIS deductions as an item on the invoice, James. I'll provide more details on how to do this below.
To begin with, you can enter the 10% charge for your baron and the 20% CIS deduction in the description section of the invoice. Then, record these amounts as negative values on separate line items along with the corresponding services or products.
Here are the steps:
- In the Get Paid section, select Invoices from the left navigation panel.
- Click Create Invoice and add the relevant products or services.
- In the description section, label the deductions as For your Baron 10%, CIS deduction 20%, or your preferred name.
- Input the 10% and 20% deductions as negative values on different lines and specify the Quantity.
- Once complete, select Review and Send or Save.

For more information on sole trader features, you may find this resource useful: Introduction to QuickBooks Sole Trader.
In case you want your customers to pay their invoice directly by direct debit, check this article: Create and send an invoice.
You can always get back to this thread if you have follow-up concerns about managing invoices. I'll be around to provide further assistance to you.