.... have a limited life, and although I've managed to extend some for several years. two failed irretrievably earlier in the season, so today's major task has been pumping water from the damaged tanks and then replacing the taps with metal ones which are much more positive in operation and will hopefully be longer lasting, too.
The first installed without issue, but the second insisted on leaking. In the end I made an extra-thick seal from some material I found in my tool kit and that has done the job. Now all we need is some rain to fill up the empty ones!