The Computing Service Lapwing facility is available in the WGB and Cockcroft 4. It can be used by anybody with a Raven account without further authorisation.
It is also possible to issue temporary "tickets" for use by visitors. To issue a ticket go to the Lapwing administration page and click on "visitors". The procedure should be largely obvious from this point on. The facility for issuing tickets is available to members of the Lapwing admin group; members can add further members.