Eligible organisations {by TOG - for a .ac.uk domain name} would be:
higher education establishments;
further education establishments;
sixth form colleges;
specialist colleges, which aim to promote opportunities for high quality education and training in residential or day settings, for students with learning difficulties and/or disabilities;
adult community learning (ACL) centres which receive direct funding from their Local Education Authority.

Tertiary education is defined as a programme of learning provided to persons over the age of 16, which is intended to lead to the acquisition of publicly recognised qualifications , such as:
a vocational qualification or GCE A Levels or a qualification awarded by the Scottish Qualifications Authority, such as Scottish Vocational Qualifications and Higher National Qualifications ;
a higher diploma or certificate ;
higher education , such as a course of undergraduate study;
a course of post-graduate studies (including a higher degree course);
a course at a higher level in preparation for a qualification from a professional body ; or

ii. part of its set of core activities is to conduct publicly funded academic research where a reasonable proportion of the results are placed in the UK public domain; or

iii. its primary purpose is to provide support (other than teaching) for organisations that work with, and provide other services to, tertiary level educational establishments or the associated research community; or

iv. it has the status of a Learned Society , which is a society that exists to promote an academic discipline or group of disciplines. Most learned societies are non-profit organisations, whose activities typically include holding regular conferences for the presentation and discussion of new research results, and publishing or sponsoring academic journals in their discipline. Some also act as professional bodies, regulating the activities of their members in the public interest or the collective interest of the membership.

guys you need a .ac.uk email address to use this.

hence its basically universities only, unless colleges give u an ac.uk address?