After a year and a half you should be able to look into unfair dismissal. You should also be able to look into what methods the employer has to us to reprimand somebody. You should have been issued a verbal and then written warning.
I would fight this if I were you. Go to her superiors and fight your corner. I got shafted by a former employer and when she fired me she told me straight out that as I hadnt been there a year (I was there 10 months)that I hadn't a leg to stand on... and she was right. I was sacked because the manager had a friend call to ask for a former employee's number. I didnt give it out, but they said that I had intended to. How could they possibly sack me for something that I hadnt done? I found a job a short while later, and am still with the company now. This could be a blessing in disguise and things may go your way shortly.
All the best and I hope you find something else soon!
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.