Arkle - you intrigue me...
Who was it at "The College" who denied you access to ATCO training?
4 ex-assistants were on the last graduation from Hurn, with backgrounds ranging from "young, attractive, ex-simulator ATSA 1" to "ex-Gatwick lighting board ATSA 4 of indeterminate vintage". [both very nice people ;-)]
All went through exactly the same selection procedure as non-assistant applicants, some after more than one attempt. The selection is handled through NATS Recruitment and is not a function of the College. The only reason that candidates aren't accepted onto a course is lack of suitability measured against the same criteria as everyone else.
What answer did you expect from the CEO?
If Mr Barron had said anything to cast doubt on the selectors, or had reversed their decision, I fear that the repercussions would have damaged NATS credibility as an organisation that trains ATCOs to the highest standard. it would also have pi$$ed-off just about every controller on the planet, plus the aforementioned Recruitment & Selection personnel, who are doing a damned difficult job to the best of their abilities.
Assistants within NATS are being trained as controllers and this will continue as long as there are assistants of the calibre required to make the grade.
Keep applying. If you are good as you think you are, you will be accepted. If not, be a happy assistant. NATS needs them too.
Whatever you decide to do though, don't fall into the "I'm good-enough, they just won't let me" pit.
DwB