You do not need to be a member of the league to race in Central CXL events.
All races have online entry which closes at 23:55 on the Tuesday prior to each race. Pre-entry is cheaper and all entries are gridded irrespective of whether you are a league member.
All races have unlimited entry on the day in all categories but there is no on the day gridding.
You need to compete in at least 4 events to qualify for the league standings, but if you complete more than 8 your best 8 will be selected for your ranking and updated after each subsequent race.
Entry to all races is via the British Cycling site.