@Jemma
Afraid I'm going to have to call you up on some points there;
The RN of 1914 had many, many dreadnoughts, from the original 1906 12-inch HMS Dreadnought, and three classes of very similar ships (about 12 ships IIRC), to 20 so-called "super-dreadnoughts" that followed HMS Orion, carrying 13.5-inch guns, including the superlative 15-inch gunned Queen Elizabeths that were fast enough to accompany Beatty's battlecruisers at Jutland. The many pre-dreadnoughts were used in less intensive affairs such as the Dardanelles campaign and HMS Canopus was involved in the Falklands battle hunting Gneisenau and Scharnhorst under von Spee.
The Kaiser's navy, on the other hand, was composed of about 15-20 dreadnoughts, usually carrying 12-inch armament, and indeed I believe they sailed into Jutland with pre-dreadnoughts in Scheer's High Seas Fleet, whereas the British did not have any, just dreadnoughts.
Another area of comparison is the design aim of the ships - the British Empire still spanned a lot of territory so they designed far ranging ships of superior sea worthiness, range and endurance, whereas the Kaiser's ships were generally considered to be sturdily built, but as a consequence of that lacking the legs or comfort for crews to go on extended sorties. They were designed to fight in the confined spaces of the North Sea close to safe harbour, whereas the Royal Navy had to choose to weaken protection for extended range in protecting the Empire's trade. Sir Jackie Fisher, who created the concept of the dreadnought, went on to create the battlecruiser, designed to outrun what she couldn't outgun, and outgun anything that could catch her. These ships were woefully underarmoured, and the final designs such as HMS Furious were armed with the most massive 18-inch guns, but barely 3 inches of armour on the main belt!
During the Battle Of Jutland, Indefatigable, Queen Mary and Invincible were all lost to catastrophic explosions, but it has been shown that the designed "best practice" was not being followed, as highly explosive cordite was stored everywhere for ease of access and the flashguards were removed, something that cannot be blamed on the ship design, but rather the all-out aggressiveness of the Royal Navy ever since the time of Nelson. One major problem that Beatty had during the early phase of the battle when he lost two ships was he was firing at Hipper's dimly sighted battlecruisers whilst being silloutted by the setting sun, a most unfavourable situation, but his entire purpose was to draw the German fleet into Jellicoe's Grand Fleet which he did superbly. Jellicoe managed to deploy his fleet to cross the "T" of the opponent, but Scheer's fantastical "Scheer Turn" saved his own fleet, combined with the distraction of the suicidal Death Ride of Hipper's battlecruisers, which they got away with due to the closing darkness and Royal Navy communications incompetence.
HMS Hood's situation was just bad luck IMHO, sending an old ship out against the Bismark. Hood was never seriously upgraded like many other ships, as she was out showing the flag everywhere, so she never got the increased armour, redesigned protection schemes and uprated machinery that other vessels got, the most extreme of which was HMS Warspite, who was basically a new ship afterwards! I agree with the thought that it was the secondary armament that caused the explosion on her - her 5.5-inch guns were still the old-style single, non-turreted emplacements, with the ammunition feeds being essentially open to all and sundry. It was unfortunate that Admiral Holland refused Captain Leach's offer to let his newer, much more heavily protected HMS Prince Of Wales to take the lead in closing with the Bismark and Prinz Eugen, as a KGV-class battleship could probably have come through the battle as the main target better than the old lady of the fleet...