Also 6 or 13 night duration. Not an issue for me I’d just go for 13. But maybe some folk want a full week not 6 nights.
When the flights routed ex Stansted, perhaps it wasn’t such an issue to do 7 night ex STN back to LCY if you are based in London or the local area. Doing SOU-JMK-LCY just to get a 7 night duration probably isn’t such a viable option to most.