Hi - I hope that you are Doing good !!

Yes this is doable
Can you try the below steps:

Click and drag to select all the objects in the swimlane where you want to add space
Try grouping them by 'Group from the context menu
you can move them down together dragging one of the selected objects downward

This will move all the selected objects while maintaining their relative positions with each other
After moving the objects down, youable to make out space above them. 

You can add additional objects or text in this space as needed to insert new steps or elements into your process flow

Hope this helps and happy to assist further !!

Thank you very much and have a fantastic day!
Warm regards

thank you!

where is the “group from the context menu” please?

I can only do what you suggest within one swim lane - i could do this before - what i need to do is be able to select everything below a certain point and move the whole lot down - as the process moves from one swimlane to another

thank you

Hi @sarahgeoghegan, I wanted to add a few more tips to @Humas1985’s great suggestion.   

I recommend clicking the header of your swimlanes to select them, then clicking the Lock button in at the right end of the toolbar and choosing only the Size and Position option. 

This will force the swimlane to stay in place and allow you to more easily select portions of your flowchart within them. From there, you can click-and-drag to select the portion of the flowchart you want to move down, or use the Group function that @Humas1985 mentioned to keep it together. To access Group, first select the lines and shapes of the portion of the flowchart you want to move, right-click, and choose Group. If you choose this method, ensure that you don’t also select the swimlane itself in the group. 

I’ve demonstrated my click-and-drag method (after locking) below.

I hope this helps!