I personally think that the snake pictured has a very jungle like pattern, especially from the end of the neck up through the head.
I am not a strong supporter of either side of the "mongrel" debate, however I do believe it is inevitable that "designer" snakes will become very prominent and popular in Australia, I just hope that the pure locality ones are not lost in the process, I simply posted that picture as an interesting specimen that was "said" to be a pure coastal, the fact that the breeder has absolutely no objection to crossbreeding would suggest that they have no reason to lie, although this in itself does not assure the truth is being told.
I would be interested to know how one would identify a true pure coastal in the wild if it looks like or better than a real jungle? If it is based on the location, how can you be sure that a jungle hasn't moved out of its normal locality and started breeding with coastals or whatever other compatible snake it encountered? Could the ones seen in the wild be a natural integrade of coastal and jungle?