I'd be interested to see what that's all about Normailson as I've walked past those signs (I live in the area) and the person has gone to great trouble to have them all looking exactly the same way.
If you look at them closely, they are all the same replica print. The only logic I can see is the person wants you to think that it's a special deal on the one house but it just looks like another way of fleecing the unsuspecting (and uneducated) public of their hard earned...
cheers
B.D