Tilde Key Issues - UK Keyboard - Can't move pattern without moving object

I'm wondering if someone can help me with the ability to move a pattern in a square, without moving the square itself??

I've looked at so many discussions on here and tried so many different "fixes" for people, including keyboard shortcuts and reboots. I've pressed so many keys to try and find one that might work, and still no joy. I used to be able to use the button directly to the left of the 1 on a UK keyboard, but recently this won't work anymore. I don't know if it's because I've had a new laptop, or something else going on with Adobe but I don't know how to fix this and it's driving me mad having no short cut to use! 

Any help would be much appreciated - not sure what else to try!