is this extension supposed to look like its dodgy?

For that sort of money you'd think the builder would have put some form of cover over the back concrete slab/alfresco area. It just looks weird as it is.
Very popular in Canberra at the moment. In fact there is one suburb (Crace) where you HAVE to use at least two different textures (ie, wood, brick) in your overall design in significant area's as part of the restrictions placed on building there. The idea being that all the residence are supposed to end up looking different and 'unique' - the actual result in my opinion, just make them all look the same.
fair enough,

to me it really looks like an add on job, so it almost like feels like an old house trying to be converted into a new one with the extension,

I personally think its hideous, but if thats the trend, then thats the trend