Here in Canada I was able to get everything done in 2 weeks. Took just over a week to mail my passport to the consulate and receive it back with visa. It is possible but it may depend on the consulate.
Here in Canada, I applied for the COE before receiving my visa and it was fine. Received the pre approval and then received my passport back in the mail the next day. Then I completed the COE for final approval and received my COE within 24hrs of uploading my visa, asq, and insurance.
Check the posted dates on the embassy website. I was trying to help a friend out from the UK today and the embassy info hasn't been updated in a while and is still showing only entry requirements from last year. While most countries are allowed to apply for Single entry Tourists Visa at the moment I don't think it's permitted from the UK.
if this is for COE. After initial application you should have received a reference code. Then wait for pre- approval email where they ask for supporting documents ie Flight ticket, Insurance, ASQ booking. Now I'm at this stage and waiting for final approval. Good luck.