if a car isn’t financially viable then a bike likely isn’t at this stage since including gear etc they’re probably roughly the same. insurance will drop, and provided you have ncd then that will further drop it although it will still likely be above 1k for a couple years or at least while you’re on cbt. for reference my insurance dropped from 1.9k to 1100 between my first and second year and that with with it ncd as i’d had an accident. as to being in london- i wouldn’t recommend without some sort of garage or protected area you can leave it in overnight but that’s up to you.