The miserable performance of the RN Mediterranean squadron at Alexandria is a prime example of a lack of accuracy. It wasn’t enough to have guns that could send shot flying for miles, it mean nothing if it missed the target. It was standard practice to aim the big guns by sighting through the bore from the open breech. It was well known that certain smart ships dumped their monthly powder allowance overboard rather than mess up the perfection of their bright work with nasty powder smoke.
At Alexandria the RN showed a high degree of accuracy, and silenced all the enemy forts. The issue was that the GS percussion fuses did burst the shells reliably, with about half the shells that went through packed earth failing to burst. The British have a tendency to dissect every action and look for things that could be improved upon, and hence a lot of reports of the failure of the fuses to properly function has made. There are other nations that ignore the fact that their equipment doesn't work properly.
They'd had similar problems with the Moorsom fuze, which was a nose-percussion worked well against ships and stone/ brick fortifications, but was found to be unreliable against earthworks in 1855. That was replaced by the Pettman base-percussion fuze, which worked well for the guns of the time, and was still the fuze in use in 1882.
However, the propellent had changed. The Pettman fuze was armed by the rapid acceleration of the shell with common powder. With prismatic type powders the acceleration was lower and the fuse did not reliably fully arm. Against harder targets they still worked, and no-one had done the experiment of a bombardment of an earthwork to realise. The fuze was modified easily enough, by weakening the restraining cup.
You are however dead wrong on how the guns were fought.
In 1829 William Kennish proposed
the idea of laying all the guns to converge and firing them simultaneously to get a tight group. It was immediately adopted. His "theodolite" evolved into the gun director. On the broadside ships the gunners still pulled their lanyards individually on a signal, but by the 1860's an electrical firing circuit was utilised and the gunnery officer aimed the guns from the director (with the gunners setting range and elevation individually), and fired them electrically. The system was named the "director firing", and the theodolite station became the director. The
manual refers to using it as "firing by director". Ships still had these directors (called Elliot Directors after the admiral) installed in the 1890's, with pre-dreadnoughts having a pair in the superstructure on specially constructed armoured towers.
In fact practice was a fire-control officer in the director directing the guns, and fired them with an electrical circuit. The problem at Alexandria was that it was found that in the turrets the voice-tubes the fire control officer used to communicate with the turret were difficult to hear during an action. Henceforth electric telegraphs would be installed to communicate between the director and the turrets (the broadside ships didn't have the problem and fired under director control).
Fisher's
Inflexible hence couldn't fire by director, and the two turret captains and four gun captains fired independently, from their fire control positions at the aft of the turret using their own optics. The position is clear on the turret layout (there are three positions per turret, the centre one for the turret captain, and two wing positions for the gun captains):