I think it is easier if you have previous cabin crew experience especially supervisory experience. I worked straight off as a P/T Purser with Excel Airways for a couple of years & operated a 5 days on 9 days off rotation, flights were rostered thurs to mon with the 9 days off & you only operated on the short haul fleet.
I believe Astraeus, My Travel & Excel all offer part time to junior crew as well. I also knew a girl who used to do freelance part time with European Air Charter, but I think their only recruiting at Birmingham & Manchester at the moment.
good luck!