i think that if you can take your time even looking now for what you want to be in so that when you are ready to move you wont just take anything 

Personaly if your going for flats then i  think that flats that are in a  medium to big block are often the best to work from as once the client is inside the building they can be going anywhere  i dont know where your locatated but 2bed 2 baths one  en suite  typs  are ideal as you will have your own space that is just for working from and can lock the door when finnished 
   
 look for things like spyhole in the doors so that you can see who is there ,  pick ones that a fair amount of flat on each level not ones that just have 2 or 4 flats on each landing       
also ones that have a code that you can use to enter as well as a intercom as well as if all else fails you can tell the guys what code to punch in to get access  - ( they are normally complicated so they wont remember )

this might sound sexist as well,  but if your renting privatly from a landlord  then  women land ladies  tend to be more shall i say emotive and more likely to have shit fit if they find out what your doing  especially if they once lived there  in the past and it was once there home  ( not always the case but worth thinking about )

agencies can be good if you pass the credit check,  make sure your deposit is in a protection scheme and that you get an inventory   
when renting there are clauses about not running a business ect but then again you would have to be caught  its not something that i would imagine the police  would be interested in  and as you say  sometimes you have to take a chance

also if your renting privatly try to find out if the landlord lives in the block or nearby or if they have more than one tennant in the block  all this is worth knowing and its generally easy to find out with a few choice questions
 
there are lots of threads on here about getting the right working place with lots of other good ideas and suggestions so have a look so that you can get the right flat

really really hope you put really nasty stinky weed smoking partying obnoxious students in your house when you leave to piss her off   

 Thanks girls for your advice its just nice to be able to talk about one's problem to others doing the same work,
  my husband and myself have made our mind up to try and get out before next summer.
 Will take on board all your advice when looking for a flat that is more discreet where one is less noticed in general.
  I understand when renting you have clauses and to entertain callers falls in the clause but life's  all about
 chance and survival and a bit of luck am afraid.
 Thanks again for your time. X
 

Ah another self righteous neighbour eh?
 They can't do diddly squat so just ignore them.