My end date for Vat submission is wrong? Can you help

You can edit it, crolfe50.

Let me show you how to edit the end date of your VAT return. 

1. Go to the Taxes menu and select VAT.
2. In the Returns tab, click Prepare return.
3. At the top menu edit the End date.
4. Then, Submit to HMRC or Mark as filed. 

For more details, you can use this link on how to submit a VAT return in QuickBooks Online.

Keep me posted if there's anything else that you need help with. Take care and have a great day!