Student Visa Fee at the Embassy?

So I am in the process of moving to Japan for school in July and I am expecting my CoE to be sent in a week or so, at which point I will book the appointment with the Embassy in London to actually obtain my student visa. However, while doing my research on the process I came across some conflicting information regarding if there is a fee or amount of money I need to give to the Embassy during this process.

I know there are agencies out there that offer services to do this sort of thing for you, for a price of course. But I am getting conflicting information on if I myself go down to the Embassy in London with my visa application form, passport, CoE, photos, all the stuff they need, if there will be a fee I will need to pay at the time of submission, or to collect my passport back once accepted or anytime during the process of getting the student visa sorted out.

I have been getting help from the school and gaijinpot throughout the process of moving to japan so I have already paid for the application fee that the school required to get the CoE in the first place, so now I am just wondering if there is a fee attached to actually obtaining the student visa or if that is only for if you hire an agency to provide that service for you.

Any insights would be greatly appreciated, thank you for reading!