The steering lock is crap and are easyly broken, I would not reliey on it to sercure your Norton when parked, best is to use uncuttable lock and chair around a post so it can't be carried away, but if someone wants to steal your bike they will, a friend of mine has just had his old shovel stolen it was locked in the lundry and chain and lock as well they lifted it and carried it out to a pickup truck, his daughter was home at the time and his neighboures as well and not one seen it happen during the day, he was only out for a hour or so, lucky he was on his new Harly at the time but he has owned the shovel for 33 years and just finished its rebuild, so if they want your bike they will get it.
Ashley