I have always thought the BA Cityflyer could be good option to add weekend capacity to IBZ, NCE and SKG

In the Summer BACF operate a flight from LCY on a Saturday morning to both IBZ and NCE. Both these flights return to STN around 1300 and remain there till the next day. The also fly to SKG on a Saturday where the aircraft night stops. They could amend the schedules easily to add a LGW sector. Such as below

Ibiza

BA8643. LCY 07:30 IBZ 10:55 6
BAxxxx IBZ 11:45 LGW 12:30 6
BAxxxx LGW 13:30 IBZ 16:10 6
BA7308 IBZ 17:00 STN 18:30. 6

Nice

BA8477 LCY 08:10 NCE 11:10 6
BAxxxx NCE 12:05 LGW 13:10 6
BAxxxx LGW 14:00 NCE 17:10 6
BA2322 NCE 18:00 STN 19:00. 6

Thessaloniki

BA2229 LCY 12:20 SKG 17:30 6
BAxxxx SKG 18:20 LGW 19:55 6
BAxxxx LGW 05:15 SKG 10:40 7
BA2228 SKG 11:20 LCY 12:40. 7