I need to create invoices going forward with RC vat on them, in the vat drop down box I have only three choices, ex vat, inclusive of vat and no vat which do i use?

Selecting the appropriate VAT information on your invoices is my priority, @fdcarroll.

When you've turned on VAT and CIS in QBO, you'll only need to enable and select the RC VAT code to apply it to your invoices. You can choose either the Exclusive of Tax or Inclusive of Tax option in the Amounts are field when creating your invoices. Then, select the appropriate RC VAT code under the VAT drop-down box. Please see the screenshot below for your reference.

In case you haven't enabled your RC VAT codes yet, follow these steps:

1. Go to the Taxes menu.
2. Choose VAT.
3. Select Edit VAT drop-down, then choose Edit Rates.
4. Click the Gear icon above VAT codes, and then select Include Inactive.
5. Use the toggle on the codes to activate them in QuickBooks. 

Once you select and apply RC VAT codes to your invoices, QuickBooks will automatically account for the reverse charge. Also, the VAT will be reflected on your return. For more insights, please head to this article: VAT reverse charge CIS.

Also, I'd recommend pulling up VAT reports (i.e., VAT Detail and VAT 100/101) to get a glimpse of your taxes. To do this, go to the Reports menu's Standard tab. Then, you can customise them to focus on the details that matter the most to you and export one to save a copy for future use.

Let me know in the comments if you have other VAT concerns and questions about managing invoices in QBO. I'll gladly help. Take care, and I wish you continued success, @fdcarroll.