Neile1
Going back to the Canaries, I think tws123 has got the upper hand on this one. EZY A320's would struggle to get to ACE and TFS in the summer from SEN's runway as aircraft performance reduces when it's hotter.
There's been times in previous summers on particularly hot days where even A319's to FAO or AGP have had to make unscheduled stops in France to pick up more fuel.
As for TCX and TOM doing more flights to the Canaries in winter, is that not more a case that they've got nowhere else to go? As I'm sure you'll know, the likes of mainland Spain, the Balearics, Greece, plus Turkey and Cyprus to a lesser extent, are too cold/wet to be viable winter destinations. But that discussion is probably for another thread.