The reason is very simple : after the Falklands war the Royal Navy adopted a design rule which states that all surface ships must have two islands. You can see

The reason is very simple : after the Falklands war the Royal Navy adopted a design rule which states that all surface ships must have two islands. You can see it in the 45, 23 and 26. My guess is that this is because of the fires which took Sheffield out of combat, the initial damage from the Exocet warhead was substantial, but what killed Sheffield and Coventry was the fire afterwards. The investigations afterwards showed that a split superstructure would have allowed continued operation including withdrawal from the combat space and low allocation of rescue resources. I think/guess that this would have been critical should aggressor forces been slightly more substantial; it would have been very easy to get into a situation where the capability to manage the rescue and recovery of struck ships would have been lost, and this would have led to a substantial escalation in casualties and probable collapse of the fighting capability of the formation - hence to a strategic opportunity for aggressor forces.