It is an org-capture issue. You have to specify the full path of the org file in the template even if this file is an agenda file. Otherwise org-capture assumes that the file is located in `org-directory'.
> Can you advise further? (Looks great regardless btw!)
Thank you, building on Bastien's suggestion I'm working on a "stealing" feature, that steals templates from `org-capture-templates' and changes the target.
Sylvain.