I'm sure ATE still do a full seal repair kit. I bought over a dozen ATE ones a few years ago knowing that good quality kits were getting scarce.
walloth + nesch has them on sale right now https://www.wallothnesch.com/en/brake-caliper-set-reconditioned-front-2-5cs-2800cs-22937.html 429 euro for the pair. be careful a lot of the ones on ebay aren't for vented rotors - some are. in either case, be sure to buy new pins and clips https://www.wallothnesch.com/en/pad...or-one-car-you-need-1-for-1-car-34-01-14.html