Another college failure who can't conceive that they just couldn't do the job. Blame everything else. Cry me a river please. You need to just face up to the fact that you obviously were not up to scratch. As you yourself stated, we need controllers desperately - what with all the impending retirements and departures to other ANSP's - so do you really think that AsA would knock you back and show you the door if they thought you were capable? After all THEIR time and money invested over the duration. Seriously, reality check please.
For the record, I went through the college a couple of years ago (will not specify exactly when as I wish to remain anonymous) and have been endorsed for quite some time now. Let's be perfectly blunt, if you know what you are doing then the college phase is pretty bloody easy. I know many will disagree, but the egocentric people this job attracts unfortunately like to make mountains out of molehills; blow their own trumpet etc. It is not that hard seriously. Final field training, as thankfully you WON'T discover, is a big step up my friend. Clearly the people that actually know what they're on about!!!! assessed you as not being up to the mark. Move on
Also, I do sympathise with you in regards to having your course extended for an extra 12 weeks, with a family of five that is completely ridiculous and you deserve (and should pursue) some sort of compensation.