You are applying for properties you prefer not what you can actually afford. The logic of this is baffling to everyone.
You are foolish to think you can survive on c. £200 after the landlords rent has been paid. It would be sensible to seek property types that are actually affordable, in different areas, albeit less desirable to you. You have this option yet it seems you would rather be homeless, and paint yourself as a victim.
You need to realise that you don’t have any leverage.