Mind if I ask how you know this? Just curious.
As to the flag plot, keep in mind that Jellicoe's information on the battle was almost completely out of synch with what was actually happening in real-time. Mis-IDed ships, mis-IDed sides, wrong location of spotters, wrong location of targets, very slow updates, gaps in information, etc. This led to Jellicoe making several decisions that we look at with hindsight as not optimal.
Having an accurate and up to date 2D map off the battle is a huge realism breaker beyond the control we have now.