Father previously told school his concerns about teacher who had sex with son Jonathan Robinson warned St Joseph's College in Dumfries months earlier Suspected teacher was having sex with his son after seeing pair flirting Sprung Dawson found 'unfit to teach' by disciplinary hearing on Monday She has also been placed on the sex offenders' register for six months Mr Robinson, now 18, has moved into English teacher's marital home 'Unfit to teach': Eppie Sprung Dawson, 27, was found in a car with 17-year-old Matthew Robinson The father of the teenage boy who had a sexual relationship with his teacher warned the school of his concerns months before the pair were found half naked in a lay-by. Jonathan Robinson suspected 27-year-old Eppie Sprung Dawson and his son Matthew, who was 17, may have had an inappropriate relationship when he saw them flirting at a rugby game. Sprung Dawson and Matthew, who is now 18, were found in a car by a police patrol car on the evening of a dance at St Joseph's College in Dumfries last December. The English teacher, who had been just four years into her career when she had seduced the dyslexic teenager, was naked from the waist down. In July, she admitted in court to having sex with her student and was ordered to complete a course of psychosexual counselling and placed on the sex offenders register for six months. On Monday she was found to be "unfit to teach" by a disciplinary panel, and banned indefinitely from the profession. Mr Robinson saw her speaking to his son at a rugby game last autumn and described her conduct as "peculiar." He told The Times: "They were at the rugby club, she was talking to us, and the way she behaved with the teenage boys was quite childlike, acting like a giggly schoolgirl. Then one of the teachers came along and she just changed. It was like Dr Jekyll and Mr Hyde. I asked my wife to tell the school, and they said they would look into it. He said that on other occasions the school had phoned him to ask why his son was not in lessons - only to find him in Sprung Dawson's classroom. Mr Robinson said that the teenager moved out of the family's farmhouse in Dumfries and into the shamed teacher's marital home three months ago after a row with his mother over tidying his room. The couple are now in a relationship. When their affair first emerged, Sprung Dawson had been married for almost three years to her husband, Ranald, a lecturer and the son of Lord Sprung Dawson, the former Solicitor-General for Scotland. Mr Robinson said he invited Sprung Dawson to his home and given his blessing for her to date his son one day, should they meet again when he was older. Suspicion: Jonathan Robinson suspected his son Matthew (left) may have had an inappropriate relationship with Sprung Dawson (pictured right with husband Ranald) when he saw them flirting at a rugby game She said she understood. But she hadn't even got into her car before she was texting him - I know because he was just sat in the kitchen playing on the computer," he said. She buys him clothes and gifts. She acts like a mum, but she is having a sexual relationship with him," he said. Although Sprung Dawson - who is now said to be working in a bar - has been banned indefinitely from her profession, she can apply to be reinstated to the teaching register in just two years. On Monday, Matthew's mother said Sprung Dawson had been given little more than a "slap on the wrist, not a punishment." Sheree Robinson, 44, added: "If she is potentially allowed to go back to teaching after two years, what is to stop her from doing something like this again? Outcome: Sprung Dawson (right) was ordered to complete a course of psychosexual counselling and place on the sex offenders' register for six months after admitting to having sex with Matthew (left) She should not be allowed to teach again, in my family's view. I think this comes back to double standards and you have to wonder if she were a male teacher whether the door would be left open for her to teach again. She should not be allowed to teach children of any age ever again as she clearly has problems which caused what happened with my son. However, a source familiar with the process said it was "rare" for a teacher to apply for reinstatement, and suggested that Sprung Dawson would struggle to have her ban overturned because of the sexual nature of the case. The Scottish Government will now decide whether to put her on a list excluding her from working with children or vulnerable adults. Sprung Dawson pleaded guilty in July to sexual activity with a person under 18 while she was in a position of trust as his teacher. She was spared jail after Dumfries Sheriff Court heard how she had been abused as a teenager by a man 29 years her senior. Mr Robinson is understood to be one of a string of young lodgers who have stayed at Sprung Dawson's home. She slammed the door without commenting when the Daily Mail visited on Monday. Sprung Dawson's parents, Alan Sprung and Margaret Holdsworth, 64, from Coventry, also declined to comment. However, the Robinsons said that they were happy to speak about their son's case "so that if there is another teacher out there thinking about it, they will think, Is it worth it?"