This project provides an ofxstatement plugin for converting the German Triodos bank's CSV format statements to OFX. Incidentally, the German GLS Bank seems to use the same csv structure, so this script could be used as well. Just keep in mind that Triodos' Swift Code is inserted in every resulting OFX.
ofxstatement is a tool to convert proprietary bank statement to OFX format, suitable for importing to GnuCash. Plugin for ofxstatement parses a particular proprietary bank statement format and produces common data structure, that is then formatted into an OFX file.
Users of ofxstatement have developed several plugins for their banks. They are listed on main ofxstatement site. If your bank is missing, you can develop your own plugin.
To convert proprietary triodos.csv to OFX triodos.ofx, run:
$ ofxstatement convert -t triodosde triodos.csv triodos.ofx