Sorry, the correct time for this event is 20.00 - 23.00. Does anyone know how I can correct this or is this something only an administrator can do?

Time shows as 20.00 to 23.00 for me - maybe your local forum settings are set to a different time zone? Not sure where you change that but it'll mean you see the times based on whatever time zone you have the forum set to...

Thanks ! I created my account when I still lived in the UK so my time zone settings were set to GMT and the event time was automatically adjusted.