Purchasing Priority Service after application is submitted.

I've read many people here who purchased Priority Service after the fact, but I cannot find any official process for this posted on the gov.uk website or elsewhere.

As I understand it I can pay the fee online, then email my receipt into Sheffield with my application number and tracking number.

Can I just follow the process and be assured of acceptance? Or is there any special prior approval needed? My application was just received in Sheffield, but I want to be assured of a decision before December.

Thanks very much for your help.

Nope, that's all you need to do.

It tells you how to do it on the VFS Global website, although they only give the email for New York, not Sheffield. They are the commercial partners of UKVI and all the information on there has been approved by them and is official.

Ah yes, I see now. Thanks very much!