HI Nick,
The Electricians drawing is crystal clear to me. The clamp is a NO push button, then a NC most likely a stop button. CR8 (control relay is sealing or maintaining contact the circuit) This is common for a start stop circuit if manually wired with buttons and physical control relays. It is a traditional way of defining the sequence, an electrians way of thinking. You are very close, please try the below.
If 1 is the start,and it is pressed and 2, the stop is not set then set the coil,
1 2
--[ ]-- --[/]--(S)-
If 2, the stop goes high reset the coil
2
--[ ]---®--