https://drive.google.com/file/d/15T9...ew?usp=sharing

The recently added upstairs loo at work is attached to a run of soil
pipe approx 7 foot long and almost horizontal.

My thick son has blocked it numerous times now, it's getting past a joke
but partly in his defence there's little suction (siphon?) when it's
flushed.

So several questions...

I affected a repair a while ago to sort a blockage which i've been
meaning to improve upon, so could relatively easily pull the lot apart
and reconfigure it?
Shall I just try to get more run on it or put a bit of vertical in where
it emerges from the wall?

Is it OK to ration bog roll to people going to the loo?

When/if he has kids of his own might there be some hope that he'll use a
rational amount of roll?