Just had that service and TPMS warning light still showing . . . grrrr. My Ediag scanner shows they replaced a different sensor to the one that Ediag flagged up - so it seems both rear sensors were on the way out - maybe the distance to the wireless rear sensors is greater than to the front sensors so they're the ones to go first. Dropped into local STS Tyre Pros (no connection to me) and they changed the other faulty sensor with a non-OEM one and still managed to get the onboard system to accept it. So if I needed to get all 4 sensors replaced it would be £320 fully fitted rather than £500 at the Subaru dealer !!