For the record. UK Equality Act 2010 is very clear about who is a lesbian.
A lesbian is a woman:
[from Explanatory Notes]:
Section 12: Sexual orientation
Effect
- This section defines the protected characteristic of sexual orientation as being a person’s sexual orientation towards:
people of the same sex as him or her (in other words the person is a gay man or a lesbian)
people of the opposite sex from him or her (the person is heterosexual)
people of both sexes (the person is bisexual).
- It also explains that references to people sharing a sexual orientation mean that they are of the same sexual orientation.
Background
- The definition is designed to replicate the effect of similar provisions in the Employment Equality (Sexual Orientation) Regulations 2003 and the Equality Act 2006.
Examples
A man who experiences sexual attraction towards both men and women is “bisexual” in terms of sexual orientation even if he has only had relationships with women.
A man and a woman who are both attracted only to people of the opposite sex from them share a sexual orientation.
A man who is attracted only to other men is a gay man. A woman who is attracted only to other women is a lesbian. So a gay man and a lesbian share a sexual orientation.
www.legislation.gov.uk/ukpga/2010/15/notes/division/3/2/1/9