Dull day today and, after a short ride, leak worsening so, stuff the dealer and TVS/Norton, both failed with regard to backup and lastly......stuff any hope of guarantee. Tank off, easy peasy, rocker cover off, not so easy but all done. Turned out the gasket had split, popped out as soon as I loosened the screws. Some suprises both nice and interesting......battery Yuasa, Japan, wiring harness and therefore probably relays, made in India, casting and mating surface finishing looks class though. Now to get some gasket paper and rekindle an old skill?