Looking for a Quiet, Private Room – £500 Budget

I’m looking for a clean, quiet room in a respectful household, with a budget of £500 per month, preferably including bills.
I work near Monument and study in Elephant & Castle. I value privacy, personal space and a peaceful environment. I’m looking for considerate housemates who respect boundaries, avoid unnecessary disturbance and never enter my room without permission.
Preferred areas: Plumstead, Woolwich, New Cross or other locations with good transport links.