How long does it take to process an OA visa application in the UK?

Here is the online manual.

%20to%20Thailand%20evisa%20v0.2.pdf

I'm not sure I'm totally understanding what you have done? You apply online for the application. You then decide if your going to attend the Embassy or do a postal application. Once you have made an appointment etc you make payment. Once you have completed payment the confirmation will be sent to your email address. You then print out the confirmation which IS the barcode. You must send the barcode with your passport OR take it with you to the Embassy.

@Pau****

Let's wait for the resident expert for the London online system

@R**

to weigh in and see what he says.

If he doesn't know the answer believe me no one knows it.

You don't say what your nationalities are or where you applied.