Last week (Mon-Sun) was the first where standing charge was more than electricity I'd bought. Am not exporting, imports are 7.5p kWh on Octopus intelligent go, or free from solar with Tesla powerwall.
It was quite sunny and I'd been using car less as I'd been ill, so by careful husbandry of charging car a bit at a time so as not to deplete powerwall too much, and no overnight car charging (powerwall makes its own mind up what to import overnight) managed to only buy £2.25 of electric all week for which I had the privilidge of paying £4.20 standing charge.