I used to be a driver for National Express, one of our jobs-as well as driving the bus, was to have to to discharge the liquid contents of the toilets into manholes that were present at various terminus and overnight type stops, feck that says I, so on one stop I did-in Immola, Italy, I drilled holes into the bottom of the tank-no more manhole covers to lift, and no more standing over a stinking cesspit while it emptied, I E-mailed this 'top-tip' to several other National Express drivers that I had met along the way