Change encrypted internal HD permissions to prevent password prompts
OK, I found a solution. If anybody would like to correct my approach please let me know.

With the storage drive (get info) -&gt; 
Sharing &amp; Permisions -&gt; 
Checked 'Ignore ownership on this volume'


The next step might have been made redundant by the previous step, but I also did the following:

Directory on storage drive with user directories -&gt; 
Sharing &amp; Permission -&gt; 
My User Profile, Read &amp; Write


This appears to have done the job, can delete and move items as expected.