You can't get a full post code from a map but you might be able to get the post district, ie the first four letters/numbers.
RAM or ROM
Postal code in a important factor to post a card or latter.
You need the city to find the postal code
If they are tech savvy then yes for example if I obtain your ip address it gives me a general idea of where you live. so having the zip/post code they can pin point your exact location. using other various tools.
Essex has 72 Post codes with-in it's location
There is a Black Horse website that has many links to get you started. This service is for people who live in the United Kingdom. The website will allow you to find your closest Black Horse Motor Finance location. Just enter your post code and find the closest location.
Go to the post office
Post your code here.
You can find a reliable location to photocopy your passport at a local post office, library, or shipping store.
One may find a Kodak store near to their location by using the site "Local Store". One would then enter data in the online form to select Kodak and their post code. The database will retrieve and display all the results immediately.
Is this location a bar? If it is I can help you out even more.
You may do, post codes can cover a number of houses (in my neighbourhood 5) and then you find the actual house by its number (you see this when you use a TomTom via post code).