I'm told that TLV is currently being looked at, however I agree that if there is an aircraft spare for almost an entire day it will probably be put to better use flying back and forth to Spain.
Also, I hear Vueling are apparently keen on operating LGW-NCL, but have hit slot issues at LGW so trying to get around them. So many have been unable to make LGW work in the past, is it worth trying again?