Just buy a used or new caliper on Ebay.
Pretty common. Not worth repairing it, usually the slider pins get completely buggered.
Got the same issue with mine at the moment and I've been searching all morning for a reasonable replacement. Any links to EBay calipers etc? Or genuine ones at £80 on eBay?
Called my local TPS this morning and was quoted £190.54 for a new genuine rear caliper. I very nearly burst out laughing
Euro car parts do 2 types of non genuine calipers. "Pagid" rear caliper (would need powdercoated) at £94.80 and "TRW" (red powdercoated) at £110.40.
Am I best buying genuine or settling for non oem? Also, is it best to replace both rears at the same time to save another headache?