Dilemma
My thoughts! Get back into instructing. With your experience you wont have too much trouble getting a foot in the door, I wouldn't think. Choose a Company that is doing the transition to a 142 organisation. They will be the ones taking on a lot of the contracted, check and training for charter companies. You will gain significant exposure to Charter organisations through that connection. It might still be a good 18 months away before many Companies transition, but it will happen. That will lead to the connections. Another 18 months instructing would have you primed and ready.
I realise you may think you've done instructing, but a different environment with career opportunities may get your passion fired up again. And before anyone gets stuck into me with "you have to love instructing and have a passion for teaching" I counter "you don't have to love flying beat up, poorly maintained, possibly overweight 206s in thunderstorms to be a charter pilot". When your at work just don't give anyone an inkling your not mad passionate about it, in either role.