Not British except by heritage, but I believe the appropriate term is 'gobsmacked.'
It's the kind of set up I would drive thousands of kilometers to conventions to stand and gawk.
Being Retired has it's advantages! 
1) Too right! I occasionally tell clerks who apologize for making me wait, "No problem. Not in a hurry, I am retired."
Oft get a satisfying glare.

2) Old Hob, even if it takes a decade, it sounds as you do finish on occasion.

Doug