Solved
When raising an invoice from the app, I can not select standard tax. A new pop up asks me to create a tax group, I cannot see standard 20% VAT.
Noticed this recently changed as before I could simply add a tax to my items when creating invoices on the go using my app. Now I can’t as a pop up instead gives me 3 options, one of those is custom tax which I think I could use but I’m worried it will not be recognised as VAT and therefore not be picked up on my VAT.