As an immigrant, I find this confusing (though good in highlighting that immigration cases can take two years to get through).
It wasn't the British who encouraged her here, she and her ex moved here and she took a job. As her partner is Italian, surely her spousal visa was with Italy (which would explain its length).
Her visa ran out. It happens to a lot of people with many qualifications - they were documented immigrants, then their documentation runs out, they become undocumented immigrants - that's how most undocumented immigrants become undocumented both here and in Australia. I'm not sure why she considers herself a special case when this happens to lots of people every day, other than she's gotten the media's attention. I'm not sure why she waited until 2011 when she was told in 2008 about her right to be here ending when her visa runs out. As she was told, she should have looked into arrangements or getting other documentation then. I can feel for her that this is difficult, but the highly trained jobs are listed on the UK's immigration website, hers isn't one of them (which is why the NHS couldn't give her a work visa, rules on that have become very strict).
The systems are screwed up and fighting for a more fair system is one thing, but the way she's coming across is that the rules should be bent for her because a she's special one - but there are hundreds upon hundreds with more qualifications and inspiring jobs just like her that are pushed out every day. The government is getting harder and harder on immigration, at the most vocal's insistence, and these things will happen in that kind of system. I suspect we'll get a lot more stories like these in the years to come as more visas come to their end. No matter the job or qualification, with the way things are going, it's going to get a lot rougher and most will leave completely ignored and the elites will pat themselves on the back for how many fewer there are.