Well I cleared this problem up by dropping one part of the Doc Grog quest that had been completed and completing the others so Doc gave me the last (I hope) item to get for his sick patient.
On a sad note the latest release has wiped out the crew quest I had already completed for Pidgley
I can't wait to find all those items again. Hope they will be able to reinstate that for me.
Now Will is willing to talk to me about dagger training.
It appears you can only carry a limited number of active quests at any one time. I am thinking it has to be around 15 as that is what i had on the books when the issue of not being able to take another arose.