I left the truth and my wife left me after asking her for a divorce.
A few days later I found a packet of condoms (one was missing) hidden in her possessions. If I presented this to her local body of elders would they consider judicial action?
Why the elders? You've left the JWs behind and you asked for a divorce so you obviously don't care about their rules on divorce.
Instead of revenge, your motivation should be protection of your assests. If you've found condoms in her things, then you need to do a little more investigative work to prove her adultery so that when her lawyers ask for alimony, you've got the goods. And you need to be cool about it...don't let on that you know anything. Tipping the elders off is the same as calling her lawyers and giving them a heads up on how to defend her. Save that information for when you need it most...in divorce court.