Ruskin School of Art Oxford, requesting to contact with my referee

Is this for an undergraduate degree?

yes I am applying for undergrad

For undergraduate UCAS applications it's normal for universities to request the reference from your listed academic referee.
It doesn't need to be someone specifically linked to the subject you're planning to study - as I understand it's pretty common in the UK for references to be relatively centralised in schools (by someone in a position similar to your HS counselor) so that's fairly normal.
They just need to be able to speak about your academic ability and potential generally. Usually in the UK I believe individual teachers will provide feedback to the person who ultimately provides the references, and the referee will then collate relevant information from this and whatever other systems they have access to in order to write the reference.
You could direct them to speak with your teachers including your art teacher to get any specific feedback to provide. You may also find it helpful to provide them this page on Oxford's website which has information for referees, and links to the UCAS guidance for applicants and referees: https://www.ox.ac.uk/admissions/undergraduate/applying-to-oxford/guide/ucas-application
They also provide some more detailed advice for teachers (including referees) on this page: https://www.ox.ac.uk/admissions/undergraduate/applying-to-oxford/teachers/advice

That is very detailed! thank you for this specified long answer, so this is a nice sign right?