Blimey we go to Hatton Locks, its managements fav walking place.

1/ It could be that you will need to flood the carb on every start up. Often I have to just slightly tickle my carb and never use the air slide. Maybe your float fuel level is a bit low. If it starts with a tickle and is otherwise ok, its OK.
2/ That nut needs to be tight to stay done up. I got a box spanner [off ebay] cos you cant get a ring spanner in the recess. use a bit of loctite and it will stay tight.
Regards