How do you match candidates to jobs?
Since October 2006 it has been illegal to discriminate against workers on the grounds of age. So why does this site collect that information? At most all you could ask would over 18 Y/N and over 25 Y/N that would cover alcohol related jobs and insurance puposes for driving positions.
Country of origin is also superfluous, as is nationality. One is allowed to work in the UK or one is not. Skin colour and inflection of speech are not criteria relevenant to any job application.
Sex, again irrelevant for 99% of job vacancies and there is talk of removing the gender specific exemption completely. It's up to the prospective candidate to decline an offer if they feel unsuited not you.