Find out if they have decent one way / inbound fares. Then fly them both. And put up the Icelandair vs Kuwaiti Trip Report
I'm only here as I also couldn't work out what routing they possibly compete on!
But I have flown Kuwait Airlines, albeit a long time ago. All the smoking seats were taken up by 4th rate American wrestlers going out to entertain the troops, who were quite happy to share ashtrays and and answer questions!
So I obviously have little input, but I do want to know if Kuwait Airport is still that startling pink colour?
Have you checked out Air Europa - they have some decent £1000 ish J class fares ex-Gatwick