Welcome to SW forums Antony
Hope this is helpful. You can set this option for selected items or set it to apply default on required dimension by changing under Tools > Options > Document Properties> Dimensions
Break dimension extension/leader lines
Specify the gap in broken extension and leader lines.
Break only around dimension arrows
Select to display breaks only when the lines and arrows intersect.
You might also find this post helpful for your future reference.
It is best not take the leader across the horizontal line of a dimension. That is the first thing they teach you when you get your drafting degree. You only do that when you have no other choice.