the plot thickens

luckily or unluckily whichever way you want to look at it, the frst has a 90degree elbow there, so i dont think open mouth or semi closed would make so much difference, think ill look into merging the 2 sections of the elbow though, a lot less work than running a seperate waste pipe and judging by those pics youve just shown me, is the way forward

thanks for the pics and info