55K should show needing brakes. A well used MINI can chew brakes up quick and previous owner my have done short braking ( wait til light changes to brake ) and heated rotors or even track days. I replace pads every 25K and rotors every 50K because of track times. I did a full set of drilled and slotted rotors $150 and EBC pads $180 and stainless brake lines $100 and sensors $50 just on Ebay. dealer wanted $1200.
Charlie Croker ,BRG 03 Cooper S, SCCA Solo, PDX, Time Trials, RoadRally, and Stella, 011 Oxford Grn Countryman S, with complete Sport Package, stock at present