Thanks, I'll do that.
Join the merchant's guild, and then explore the basement (the cat got stuck in one of the rooms, and will escape when you open the door). The 'best' way to join the guild is to restore Maria's reputation; talk to her in the poor quarter, if you have not done so already, then return to Verdistis...
One cat successfully recovered - and another 2 quests completed as well, the 1st is Restoring Maria's Honour, the second is on Diana (the little girl) gives you - someone's leaving goods in a hen coop near your (Malcolm's) house.