Starting out, obviously I have slight strength imbalences, as your body favours one side for a particular thing more than the other.
Most notably, left tricep stronger than right, right bicep stronger than left etc.
I heard from many places to work these out to start with, and I've heard from many other places saying just start lifting the damn weight, and if it carries on and causes problems, sit down and sort it out for sure.
Which would be best? I'm gravitating to shut up and lift right now...
You're right. You should shut up and lift right now. However, while you do, spend more time on free weight exercises that allow the use of both sides individually, like most dumbbell movements. Most beginners are in your situation. Your body will balance out as long as you don't ignore one side in favor of the other as you train.
I thought that a compound like bench would even it out quicker and naturally.
In your scenario and advice I assume that if he went with isolated individual movements like dumbells, then he would SEE the weaker side and HAVE to compensate...and build it even...am I in tha ballpark?
Well, you can only want to be benching as much weight as your weak link can handle. So by doing that, your strong arm isnt getting the maximal stimulus, but the weak one is. That way, the weak one will improve faster than the stong one, and youll even out.
Along the same lines, a way to even yourself out, is to do a set that taxes your weak part maximally, than do the exact same with your strong one. (still using the same weight you used with the weak one)
While compound movements may be good for overall basic strength building, allowing each side to work independently would be the quickest and most logical way to allow your body to build the neural pathways leading to increased function and handling of the weaker side.
He has one side weaker because he never taught himself to rely on it. In movements requiring each side to work independently, the lagging side has no support. It is on its own and has to build the ability to adapt to this.