I wonder what you suggest I should do.

Well that's old nags for ya. They've probably been pooing in the
street and flouting minimum tread depths on their hooves too.

Like it or not, the water regulations are as they ahttp://
www.opsi.gov.uk/si/si1999/19991148.htm

Most likely your local suppliers couldn't care less about what your
old nags get up to - but might be more concerned about a householder
that deliberately set out to draw water from the supply without it
registering on the meter, no matter how they did it.