There was a strange smell in the kids loo this morning. After thorough investigation I ruled out the possibility of stale food, dead reptile or a forgotten diaper. Drain issue, I thought. So I asked the plumber to check when he popped in for his weekly visit. After a very thorough 2 second examination he told me with much confidence that if I left the bathroom door open all the time there would be more ventilation and the odour would go away!
He's paid a monthly retainer, btw.