FFS,
So much willy waving and over sensitivity.
The OP has stated that she has withdrawn her application due to the financial implications of a move. This situation is something that occurs more frequently since we (collectively; I personally didn't) voted to reduce the training wage; it makes it more difficult for people to leave one career to change to ATC. This decision is even more difficult in the current economic climate as leaving a secure job, to try to train as an ATCO, is more of a 'risk' if one eventually does not succeed.
As to age, it is a pretty well established fact that as people grow older the brain does find it more difficult to adapt quickly (which is totally different to learning from books etc, in fact there is some research which shows that for book learning, age is an advantage).
The thinking process becomes 'less agile' - something which can prove to be a problem in learning jobs such as ATC where the ability to think on your feet is required.
Experts have said for a long time that when younger, inexperienced ATCOs can rely on speed of thought process etc to help them in sticky situations. As controllers get older and the brain becomes 'less agile' they have the luxury of experience to help them out of sticky situations.
As for trainees failing at busier units yet validating at quieter ones, people from both sides forget one major factor.
Some people (by no means all), think that validating at a 'quieter unit' after failing to validate at EGLL or LACC (for instance) proves that their unit is harder/more complex.
On the other side of the argument I have heard some OJTIs claim that they must be better at training because they manage to validate people that EGLL/LACC cannot.
We also hear of trainees who think that they have been hard done by at TC (thinking of one case in particular now) because they went on to validate at MACC.
What none of these people seem to remember is that when succesfully validating at 'quieter units' thay have had the luxury of many hours of previous training at another unit.
These hours contribute hugely to the eventual validation.
The system works thus: under the UTP you have a certain amount of hours to train someone. If they do not manage it within that time frame (including extensions) then they have to be failed. This means that someone who moves to a quieter unit often has 400+ hours under their belt already before re-commencing training.
Anyone who does not think that this is a factor in later validation is bonkers! In fact you could argue that if it takes 800 (400 original plus the 400 at the new unit) hours to validate at a 'quieter' unit, then the ability of that trainee is still open to debate. One hopes in such circumstances that the person continues to learn after validation and that experience helps them to become a more rounded and able controller.
As a friend of mine said when asked at his technical interview if he though anyone could become an ATCO, 'given enough hours, yes'.
At every unit there are some tasks that are easier than others. There are some very easy sectors in TC, but also some very difficult ones. Thats why to get band 5 pay you have to meet the MUR i.e. you cannot loaf on an easy sector/airport all the time.
The same is true unit to unit - taken as an overall comparison, some units are more busy/complex than others. That's not to say though that within those quiter units, there are not some tasks that easily rival the complexity/traffic levels of the 'busier' unts.