The lady two doors from me called me in to look at her extractor over the cooker as there were maggots falling down from it onto the cooker. When i took it apart there was a dead rat on top of the fan , and the maggots where falling off of that . It looked as though the rat had been in the wall cavity, and chewed its way into the flexi ducting. Also at an office block that i do some work at a mouse had poked its head into a 20 mm hole in some skirting trunking and bitten a cable and knocked out half the IT department.Its back end was still sticking out of the hole.