As far as I'm concerned, I've determined it aint worth the hassall and risking the negative so i just send through a mutual close, and request they accept it, so I get my final value fees.

That was not the best thing to do.  He can reject the mutual cancellation and leave you NEG, or he can accept it and leave you NEG.  The only time he cannot leave you FB is if he does not pay and you close the case.  I close NPB cases on the 4th day the moment the option becomes available.