After loads of investigation, I managed to find out what the cause of the issue was for our project. It worked locally (running through Xcode itself) but for our CI machines it didn't (which is where we use CLI). But basically we were building our UI test bundle on the x86_64 architecture and excluding arm64. You need arm64 (which would make sense) for the M1 Simulators to swipe correctly. This small removal solved all of our problems and the UI tests work as they should. Check your Build Settings in your project.
# Before
xcodebuild build-for-testing -workspace ProjectName/ProjectName.xcworkspace ........ EXCLUDED_ARCHS=arm64
# After
xcodebuild build-for-testing -workspace ProjectName/ProjectName.xcworkspace ........
Some solutions online will tell you to run the simulator in Rosetta - don't, it doesn't solve the issue.