thanx, I do not know if the V12 has less space inside the V than the V8 but it is very tight in there, I will strip the valley cover off today, I spend half a day yesterday to remove the 12 injectors, two were stuck like anything, I was so glad that the second injector I tried to lift out came out very easy otherwise I would not have known how to get them out. In the end I just took my time, spray a lot of Q20 oil and left the oil to soak in, then I rotated the stuck injector sprayed again, waited again until I could them all out. I will definitely replace the o-rings as well.
I am in the same boat than you, I can not see were my water is disappearing as well, hence my reason to work towards replacing the water pipe inside the V. The previous owner has replaced all the radiator water pipes as well as the complete radiator to try and solve the water issue. I am hoping to find something definite else I will have to look at the alternator o-ring next.