Gerona
Dont think the start of the NCL - Gerona will affect the Durham Tees Valley flight at all. In fact I would expect it to do better than the NCL service as there is competition at NCL from Easyjet to Barcelona and I think a few other charters from NCL. There is no competition on the route at Durham.
Generally I would think all the GSM routes will do very well, again with no or little direct competition, unlike NCL where there seems to be on some routes numerous operators in direct competition causing over capacity.