YuYu is a friendly host! Her house was clean and comfy, I spent quite a lot of time in her house, cause I was looking for my longer stay in London. She shared some information with me which is really helpful.
And luckily I have confirmed my longer stay just 3days after my arrival, so I have to check out earlier than I planned.

There's a big shopping mail nearby her place, it's just 15mins bus travel to the mall. And further more, there's some supermarket and cafe right next to the Grove Park station, which is quite convenient. However please spare more time for your travel, sometime the train will delay, (Which is normal in UK I think) so be prepared for that.