Interesting, I haven't checked EF myself, but on the VS site, if you book a one way on the 11th March it gives you a flight (albeit at £3,500 one way so a full J), but doing a return on any date it doesn't give any option, not even a full J!
You wouldn't get a Z/I/C/D now anyway as you are inside the advance booking period.
Strange, EF is showing me availability. ?| (Sorry, screenshot too big to post from iPad)
Legend Create Flight Alert View Flight Details View Seat Map Departing Flights Search Departing LGW on 03/11/13 10:00 AM for HAV Returning on 03/25/13 12:00 AM Flying VS
Departing 03/11/13 03/11/13 - Mon
FlightStopsDepartArriveAircraft Frequency ReliabilityAvailable Classes (Click on the class code for details) 0 Connections VS 63 0 LGW 03/11/13 11:35 AM HAV 03/11/13 5:30 PM 744 M,Th,Sa 42% / 47m J7 C7 D7 I7 Z7 W4 S4 K0 Y9 B9 R9 L9 U9 M9 E9 Q9 X9 N7 O3
oh well, will call FC tomorrow and see how much, if available, they want to upgrade me from PE.