hey abz,
I don't know if its compulsary to have them, I presume it would make it easier but I havent seen anywhere mention A Levels.
If I remember rightly recruitment say at the minute the process start to finish is 12 months if you pass it all first time round.
Stage 1: Tests and get to meet and talk to an ATC,
After Stage 1 you do a personality questionnare,
If you pass the personality questionnaire then you fil out an extended application form.
Stage 2: Computer tests and a structured interview.
Not to certain after Stage 2 but some-one else will know.
At the college they reckon you will be there between 9 and 12 months, if you pass everything first time round.
Hope this helps.