Okay, having checked my translations of Rasenack, there is a third 8" hit described by him. However, it is described a little different than in the English accounts. According to Rasenack, it passed over
the belt armour (explaining the lack of photographic evidence correlating to Millington-Drake's description) and through an armoured bulkhead before exploding about 40 cm above the panzerdeck. He wrote that AGS was in a hard turn and heeling over at the time so it passed over the panzerdeck instead of striking it. He further comments that since at that range, given a 0 target angle, a 8" shell could penetrate 140mm of belt, so had it been lower at a favorable angle it may have penetrated to a machinery space, given the belt was only 60-80mm. 140mm penetration corresponds to about 20km battle range (German 8" gun), and the hard turn would likely have been the turn to avoid crossing the T of Ajax and Achilles.
and that Exeter scored the first two hits of the action and that her initial fire was more accurate than GF's.
Indeed it does. Or at least about equal to AGS's shooting. Remember AGS also scored with its 3rd or 4th salvo. Opening fire at 0617 AGS scored at least 7 hits during the next 17 minutes or so. That would be with about 102 rounds, estimated.
How many visualize this battle: a prolonged slug fest with both sides scoring hits few and far between is wrong. The first 15-20 minutes of battle was fast and furious with both the Exeter (at least before the hit on B turret) and the AGS shooting exceptionally well at ~18-20km battle ranges. At 0638 the battle turned into a stern chase for the next 40 minutes and like most stern chases high hit probabilities are not likely.
After Exeter was reduced to 2 guns under local control at 0634 it was not likely it would score any additional hits. This further indicates that Exeter scored it hits early and was shooting accurately despite the long range.