Have just adopted two 10 month old brothers from rescue centre.They were confined to one room for the first week and have had the run of the house since Thursday. Initially they both were using their separate litter trays without any problems. Now the shyer of the two has pooed on the sofa two days in a row while we're in bed - I know it's him as caught him in the act first thing. His litter tray was clean at the time. Not sure what I can do to stop this from happening again. Does anybody have some advice?