Thanks for the update, @WiggaramaUK. 

I'd be delighted to provide additional insights regarding this matter.

Yes, you can work with QuickBooks Online using the incognito window.

Also, you can go back to your regular browser and try clearing its cache since it works perfectly in incognito. You can also use another supported and up-to-date browser to narrow down the results.

Moreover, I'll be adding this helpful resource to help manage tasks in QBO: Getting Started With QuickBooks Online.

Let me know how else I can help you with QuickBooks by adding a comment below. I'm more than happy to lend a helping hand. Keep safe.