Gold St. Christopher with modes of transport on the back - possibly Concorde ?

by shell
(warrington cheshire uk)

hi

i have recently come across a piece of jewelry that belonged to my grandma, i remember her wearing it at least 25 years ago when i was a child but am unsure how old it is exactly. it has the st christopher on the front and then what i think is the Concorde on the back and also a train and a boat. i would love to know more about it , hallmarks are on the back but i can only make out s&k i'm afraid my eyesight isnt good enough to see the rest