This gets my vote for thread of the year so far!!! Loving the pictures, security measures etc and also the ever so slightly off the wall suggestions! Great read!
I can't believe a lot about whats happening to you, but mostly that someone tried to break into your hourse at 9pm! The brasen cheek of it! They might have done the decent thing and waited till the dead of night like proper crims! It does sound like you're receiving an abnormal amount of attention in that house mate, and as you said being previously owned by a dealer probably has a lot to do with that. I know you said the job centre is only round the corner, and it sounds like a dodgy as fook area, but it still seems a bit excessive to just be that to me.
In reality there isn't really a lot you can do that you're not already doing i guess, just secure the house as much as possible, and hide in the corner behind the sofa with all the lights of pretending it's not happening and whispering 'please go awaaaaayy'.
That's what i'd be doing anyway!