For college owned equipment (including equipment purchased on research allowances) repairs should always be arranged through the College IT department. Please bring the device and power supply to the IT office in the Besse building.
The College IT department are unable to provide a hardware repair service on personally owned devices.
The main apple reseller in Oxford is Western Computers who are just round the corner from Worcester on Gloucester Green. They are an apple authorised service centre so should be able to arrange repair of Apple devices covered by warrenty / applecare.
The nearest apple store is in the Oracle shopping centre in Reading, which is a 30 minute train journey.
For Oxford University members (Staff and Students) IT Services on Banbury Road offer a Hardware Repair and Upgrade Service at cost.
Other possibilities are the Know How service offered by Currys PC World Or Computer Assistance on the Cowley Road