Suitable type of Visa

[Ewilan]

Hi,

I have been invited to attend a short Summer School (4 days) in Oxford. The thing is that I am confused about the type of Visa I should apply for: a standard visitor or a short-term study visa?
There will be no credits resulting from the School and it's not a course delivered by the university but rather tutorials and lectures intended to PhD Students.

I've seen that standard visitor can do it for academic visits and conferences while short-term study visa is intended for short courses and training.. I am really confused.

I e-mailed the embassy but got no answer to this date. So, I count on your help.

Thank you!