SKOS
Don't get distracted by Rogdabbit's obsession with banding. It's just one of his/her hobbyhorses!
I think the point is that if you are only joining ATC with a view to earning £90k in 15 years' time, you will probably find that that motivation is not going to be enough to keep you going through the sometimes tough periods you will experience on the road through selection, the College and validation training. The majority of people who I know in ATC do it because they are interested in and enjoy it. The remuneration is of course good, but it's not the prime motivator.
OJTI: On the Job Training Instructor. There is an extra payment for training others in the form of a step up the pay scale and also quarterly payments for the hours someone actually trains someone else. Again, selection should be on suitability and motivation for the task, not (as in some cases) on having been valid for the minimum of two years.
Yes there is an automatically-advancing pay scale every year. So if you are successful as an ATCO you can do that for the rest of your career and you will reach the top of the scale in around 15 years. In some cases, you might end up earning more than the ATCO managers around you who are of a higher grade but who don't get extra payments for training or being examiners. That's a sore point for some people!!
It really doesn't make that much difference where you end up. The job's great, and top of the scale at Swanwick and Heathrow is now over £90k with shift allowance. At Scottish it is about £80k, reducing to about £65k at the smaller airfields such as Southampton and Luton. None of those are to be sniffed at, as you will know from a glance through the Appointments section of the Sunday papers and see what you need to do in the real world to earn that!!