I am a long stay student in France holding a type D schengen visa currently. The validity of my visa is 6months. I do not have OFII.
Your Schengen visa means nothing in itself for the UK, the UK is not part of the Schengen area and governs its own immigration.
Whether you need a visa or not depends on your nationality largely, you can check here: https://www.gov.uk/check-uk-visa/y
Though I would assume that if you do need a visa then having a schengen visa and being a student in France will give you a lot of points towards acceptance vs. if you were just living at home.