Scotts advised to spike the lawn and then soak it. Spiking it almost
killed me. Soaking it probably cost me £15 on my water meter (we have no
hose-ban here).


so that will be about 2,500 gallons - I see why you used the word
"soaking"

OK, haven't done the maths, but presumably - and thankfully - I exaggerated
the metered costs!!

Neil