One more simple answer to the question why TCUK was grounded while Condor and Scandinavia was continued is the passenger base.
TCUK had 80% TCUK passengers -> as long TC is not kept alive, there is no sense to keep an airline alive only having 20% loadfactor remaining, without having any strcutures to sell the other 80% somehow in due time.
TC Scandinavia had initially the same problem, they had 100% passengers from their nordic tour operators. But since the tour operators are continued, the airline is flying also, because it the still has its passenergs.
Condor is similar, it only has 20% TC passengers and 80% single seat and other non-TC tour operators bookings, which makes much more sense to keep them flying. If Condor is able to compensate the missing 20% TC passengers in future, they are able to survive.
regards