This is a deperately difficult area now. If a police officer (or another professional involved in your boyfriend's case) considers that there may be a risk the current safety first policy dictates that such suspicions are recorded (thank you, Ian Huntley). My wife lost her new teaching post, despite years of unblemished service, because, in the opinion of one anonymous officer, she was thought in audio recordings of stories she made for a friends website to have referenced underage sex. While her CRB check acknowledged this was not unlawful as such, it gave rise to concern. We appealed the CRB check, but the police dug in their heels. It took a substantial, cross-disciplinary meeting, at which we could not be represented. Result, one out of work teacher, never accused nor even questioned about her non-crime.
When the Independent Safeguard Authority comes into play later this year, I cannot see anything other than a tightening of the rules. Fundamentally, anyone can be deprived of their living by a rumour, and once marked, there is currently no process for removing the stain.
My advice is to get an enhanced check before having to provide one for the school if possible: forewarned is forearmed. If (as is likely), he was checked before teaching practice, all may be well, but the potential for a damaging caprice on the part of the police is still there. I wish you and your boyfriend well: I will pray that he is able to enjoy many years of teaching.