There was a taxi company in the Netherlands that had a service only for women (and men under female supervision). But the taxi company also had a service for men (and women under male supervision). So the company didn't rule out the other gender but had special gender-oriented services. No discrimination here...
I dunno about the rest of the world but in Canada it's legal for insurance to discriminate based on gender as long as they have statistics that "prove" women tend to be safer drivers. Based on this commercial I'm going to guess that, yes, it is also legal to discriminate based on gender in the UK.