Watercorp sewer maps - help

Does anyone know what that double sewer line with a slash represents? I dont think its a concrete encasement. I cant decode it using the Watercorp water waste symbols guide.

Also would this cause any problem with building? Just run the driveway down on that side with traffic able lids and have the rear houses' alfresco at the rear near the sewer manhole??

Thanks guys

 

Looks like its just a property connection mate i think the other line is a mistake

 

@Big Daddy - Concrete encased sewer is possible if it's adjoining the house.

 

I'll vote conc encased.not very clear but likely as the neighbour's block is a battle axe block and some bright spark may have thought ahead with yours. So you could be good for driveway over the sewer.
The slash is a junction 8.4m upstream from man hole

The only thing is the front house may need an additional connection out to the street main, rather than using the conc encased line

 

Thanks guys