It may be a cookie/settings issue in your browser. If you go to
http://www.wlv.ac.uk/about-us/governance/legal-information/cookies/ , you will find some Wolverhampton cookies (visitor, athens, ti, oaid, oaid_*) that are used to "keep track of whether you have authenticated to use our electronic resources". The sessionid3045 and lastaccesstime3045 cookies contain session id and a session-timer/re-login functionality. If something is interfering either with the cookies being set or being renewed as needed, then that may be causing a 're-authentication' issue. I was unable to find any Wolverhampton online materials that specified "acceptable" browser brands/versions for interacting with their site, but it might also be worth contacting their IT department somehow to explore that.