A very similar case like this happened near me. An old guy was dead for approximately 2.5 years and was only found because all his saving got used up and so his mortgage stopped being paid and the bailiffs arrived to evict him. He was found mummified and with the radio still on. His family all lived abroad and ran his business abroad for him. I can only assume they thought it fab he hadn't asked for any money from it for years. He had a flight booked that he'd missed to go over there 2.5 years before he was found and that's how they dated when he'd died, that and the date on the milk in his fridge.
Its really sad, but some people have horrible family. Or they are the horrible one. Some people, rightly or wrongly have no one who cares.
I can also easily believe that the Met police lied about checking on her. Lazy feckers