ask youself some questions.
how far is it from other work i do? can i tie it in with those jobs?
how longs it gonna take me?
its really hard from the pics on google maps mate, windows frames sills and those sun shade things - the one off of course will be more than the 4 monthly one.
you must know in your head how long it will take. hard to price it from what i can see but it would def be well over £50 per building.