Hey well done Archie lad, we have them round here too - and altho his nibs is a bit cautious when it comes to going outside when they are in full swing, the bangs, whizzes & pops don't seem to be bothering him that much
he does notice the big bangs, but only lifts his head as if to say wot the heck was that.
Not sure what to suggest when you leave him - only that if he is comfortable with noises, how about leaving the washing machine on a long cycle - so he gets used to the slosh, sloshing sound