Following further experiments and reviews of other webflow sites, based on the information that I am dealing with in my feeds I solve this by doing the following:
Add div block to top of collection item.
Add switch in CMS item for “Offset”.
Add condition appearance to the div for feed.
In CMS item, switch ON for each item in the column where I want the offset.
This will require the switches to be changed on each post, so it’s not full proof, but works. Conditional code based on the the number of post would be ideal ie. if postNumber IS odd, display offset.