My 12 year old cat who's been toilet trained since I got him and who has nicely buried his poo outside all this time, has now started just depositing turds on the lawn. No major changes lately. Worried it's old age having an effect but is there anything I can do? Have seen 'cat granules' for sale that supposedly put them off certain areas, but I have another cat who uses an indoor litter tray and don't want to upset them either if I can help it. Any ideas? TIA