Right rear caliper had seized. Left rear now also affected. Calipers, pads, discs all need replacing both sides. £1k all in inc. service and MOT pass later today. Ouch.
Frustrating thing is rear discs and pads were replaced last year with advisory of uneven wear. Lesson - should have had the advisory implications explained and changed the caliper last year. Maybe they did but I didn't hear it.
High time preference fiat thinking did this.