I have done some research of my own into this and it seems that Evernote does not have to flexibility I am looking for.
It seems ok not alone in thinking this and a number of other users have reverted to an app called Notability for general note taking during meetings and annotating PDF drawings and documents. The articles I have read by others suggest then importing these marked up document to Evernote for storage.
Its a shame that this functionality is not integrated into Evernote and that a clunky feed in from a second app is required to realise this usability.
let me know if you have any other ideas!?