He presents his case as being very borderline. 26 years ago, in the wake of a divorce, he had a relationship with a 15 year old girl, which continued for "a very long time" and was "not full[y] sexual" before she was 16. He was convicted of indecently assaulting the girl since she couldn't legally consent to the (unspecified) physical contact. He accepts that it was in retrospect wrong to have a relationship with a pupil, and also claims that, had he understood the law, that he wouldn't have acted as he did at the time.
Listening to the interview, it seems fair to me that he should be given another chance, but there are a spectrum of severity of offence and I really don't know where lines should be drawn. On the other extreme, I think it's entirely reasonable to bar those with a history of abusing children from positions where children are in their trust, but one could hypothesis ever more borderline cases. Possibly the best solution is the proposal to allow a panel of experts to consider every individual case, and accept that they'll probably often bar a deserving case and once in a while they may let through a dangerous person.
Overall, that feels more acceptable to me than the alternative of barring all people with a conviction for a sexual offence on the off-chance that they might be a danger. However, I don't have children, so probably am not so emotionally involved.