I can appreciate your feelings, Rowan. It's awful when people "don't play the game" or appear to receive something that we can't. It doesn't mean that you have permission to behave as they do, but it still shouldn't stop you from achieving what you wish to achieve.
The best way forward is to use the means at your disposal, such as annual appraisal/review and consulting your union rep (I see from your post that you are a "union shop", which indicates to me that your workplace is organized).
With respect to office politics as a whole: this can be a very destructive, divisive game. It's best to stay out of it, but to be streetwise and develop a shrewdness that will enable you to navigate your way in business with tact and without making enemies. Very, VERY few people are born with this level of shrewdness; even if it is innate, it still has to be developed.
I've worked in the business world for many years now. I made some splendid mistakes when I was starting out and left behind a few people with sore toes (from stepping on their feet

). I've been fortunate enough to have some good teachers, though, and can, on the whole, operate successfully without upsetting people in the process.
So, Rowan, mend fences if you can and put this behind you.
Best wishes,
Raindance