TatcClassOf09 - for a profession which has historically been short of qualified staff, it pains me to hear of people who go through self funded courses but then come up against a brick wall. That said, I have known guys who have self funded and got in somewhere or at least been offered a place at an airfield and done well from it. Keep trying, even for an ATSA post, I know of two people who worked as ATSAs after passing rating courses who trained at the unit they worked at in their own time and validated. Both work for NATS now and one has become a Watch Manager. Just don't give up and apply for every unit which advertises, even if you don't have everything they want.
p_robinson80 - NATS recruitment don't make specific allowances for applicants who are ATSAs but for anyone who has been an ATSA, it can only help through having more knowledge of the ATC system than those who haven't had any aviation background. I don't personally know any ATSAs who took 'ATSA qualifications' (whatever they are!?) before becoming an ATSA. If you can read, write and communicate properly (if you were educated at a NI grammar school, you've got a headstart there!), then a smattering of GCSEs will be enough. Most ATSAs I know under 40 got into the job either by failing in training at NATS, or at non NATS airport units, by applying from within.
As for your last question, not as far as I know.