AF - just found this:
"Character of victim - previous sexual history
Sections 41-43 of the Youth Justice & Criminal Evidence Act 1999 (Archbold 8-123k-123q) came into effect on 4 December 2000. See R v Kevin John Cartwright, unreported, (2007). The sections restrict the circumstances in which evidence or questions about a complainant's sexual behaviour beyond the circumstances of the alleged offence can be introduced in rape or in certain other sexual offence trials. It is essential that prosecutors are robust in dealing with applications under section 41.
At the trial of a person charged with a sexual offence as defined by section 62 of the YJCEA 1999 (Archbold 8-55x) no evidence may be adduced or questions asked in cross-examination by or on behalf of the accused about any sexual behaviour of the complainant except with the leave of the court, (Archbold 8-123k-123q).
Such evidence will only be permitted if statutory criteria are met and the court considers that it may reach an unsafe conclusion on an issue to be decided in the case if such evidence were not to be heard. Any questions asked or evidence to be adduced must relate to a specific instance of behaviour."
from here