The 'hatch' key is probably the 'hash' key (a.k.a octothorpe or pound)…
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That is alt+3 on UK keyboards.
I'd recommend you try Keyboard viewer when the 'Input source' is in your preferred language. Open the Keyboard tab of System Preferences > Keyboard and enable the option to show the character & keyboard viewer in the menu bar.
Now open the Keyboard viewer from the menu bar & press various modifier keys, you will see the on screen keyboard update & display what the output will be for the other keys. You should be able to find the correct combination by trying various cmd, alt, shift, ctrl combinations etc.