I'm not a native speaker but I'm pretty sure "Sadie" is London slang for "spotlessly clean in superb location". The apartment was simply lovely, had everything you wished for and more (a remotely operated fan with timer anyone?), and as I said was immaculate upon arrival. The location was perfect for us, with Victoria park, Shoreditch, etc within walking distance (and 6min from a tube station). The only downside really is when you arrive back home you think you need to clean more often.