If the promoter/supervisor accepts you for a doctoral project, does the University "automatically" accept you as a student?

I imagine you would receive a formal and official offer by post and also possibly by email from the University's Admissions/Recruitment department.

You should still need to put in an application and go through interview - this is because Universities have to adhere to equal opps policy and because a supervisor doesn't collect all the evidence needed to submit someone as a student.
They will want references and previous qualifications/ transcripts etc.

The application guidelines should be on the university website, and if the supervisor wants you then when the application comes in they should fight your corner or be able to give a statement saying that they think you're great.
I did my MA at the instituation I'm doing my PhD at so used my prospective supervisor as a reference.

Check the website so you don't miss any deadlines esp as there may be bursaries etc attached to the project that you can apply for.

thank you. that helps. i will def. check the website properly.