Chevvron,
I sort of agreed with your take on demonstrating prior interest in aviation etc but my own family situation shows the opposite.
My ATCO son had absolutely no interest in aviation, apart from noting that I seemed to be reasonably well paid and had lots of time off, but when he was on OJTI at TC in the late 90s the lovely Jane M***** reported that he was the best trainee she had ever had, excuse my choice of words.
My pilot son had wanted to fly Jaguars from age 8 after making an Airfix model and only reluctantly joined the Air Training Corps because I told him it may help his application for a 6th form flying scholarship. He left as soon as he had passed the Biggin Hill selection. He did fly Jaguars and years later is a test pilot with Airbus.
My own story is similar, lots of my mates in Camberley were in the ATC and desperate to fly, I wasn't. After one started nav' training I thought that sounds interesting, and you can guess the end of the story. Natural modesty makes me stop here.
There seemed to be more spotters among the ATCA/ATSA fraternity than ATCOs, particularly at LATCC & LL.
Gonzo
I don't wish to sound rude, but how come you were involved in ATCO selection at age 22 when you must only just have left the college yourself? I got my 'early go' from LL in early 2000, were you there then?