Within your Parcelforce settings in Shiptheory, you now have the ability to specify a cut-off time for when you stop sending Parcelforce orders for the current day.
This setting can be found by navigating to the Parcelforce Shiptheory page and scrolling down to access the "Advanced Settings":
Within that, you will see the option to specify your latest collection time:
Any orders that you book in after that specified time in Shiptheory will still process and be able to print, but they will book in for the next available collection day. By default it's set to as late as possible, but you can make any needed changes and hit save after to get this set up.
If you have any questions or issues from there, please feel free to Contact Support