We have your flyer on the fridge and have been looking out for Aubrey and hoping he returns to you soon.
I had a cat who went missing a few years back and he was found after 2 weeks in our neigbours garage. He wasn't thin so don't think he had been there all the time. You could try social media in case he had gone further afield https://www.facebook.com/groups/lostandfoundcatsinnorwich/ is a very active group who post about cats in Norfolk not just Norwich.