Kev, it's pretty clear that your knowledge of the charging system is not at "expert" level. Trying to get valid advice out of us is like going to a blind man for his opinion on what we are looking at.
My (unexpert) advice is to take it to a reputable service center and make sure they guarantee their work. In reading all your posts, you've covered all the points I know about and if I were in your shoes, I'd 'punt". But, get the guarantee!