Royal Army gains were left on the beaches at Dunkirk.
Royal Air Force Gains were matched by the Germans.
Royal Navy gains weren’t needed in a 1938 war, when the Germans had little to nothing to match them.
I gather that we won’t agree on what the British should have done in 1938, going to war unprepared against an unmobilized foe, or waiting. I will only ask you to take a hard look at what the Germans actually had available to fight with in September of 1938, and then in 1939 (let alone 1940).
Army divisions:
1938 - 36
1939 - 98
Navy:
1938 - 29 coastal submarines / obsolete and small surface combatants
1939 - ~40 submarines(90 by 1940), more surface units but still incapable of challenging the Royal Navy of 1935.
Luftwaffe:
1938 - The Luftwaffe had technical superiority over the RAF and Frency, but had vastly insufficient numbers to defend their ground forces from medium bomber attack. In short, I think the Germans would have had the upper hand, but insufficient number to transfer than advantage to a ground victory.
1939 - About 1500 more of the uprated ME-109E (vastly better than the 600hp earlier variants) had been delivered. These we know decimated the RAF and French airforces.
All of the new British battleships had little effect during the war, except for patrolling for German raider runs, which almost never came.
Absolutely. But that could have happened in 1939 from a 1938 war, and Britain would have been able to recover even fewer men - assuming they'd made it back to the coast. British troops in France, even in 1939/1940 were only ten percent of the allied force which was mostly French. When the French collapsed, the British couldn't do much at all. The same would have very possibly occurred a year earlier.
(Oh, and it's the British Army, not the Royal Army, just for the record - Bill of Rights 1689 means the Army is Parliament's, not the Monarchs, although he or she is their Commander-In-Chief).
Royal Air Force Gains were matched by the Germans.
Not in terms of technology. The BF109 was in general service by late 1937, early 1938. At the time of the Munich Agreement (30th September 1938), about 100 Hurricanes had reached squadrons, and the Spitfire hadn't even reached its first operational squadron (that happened within a week of Munich, though, so it was close). By the time the war started a year later, there were 500 Hurricanes and 270 Spitfires in service. From 100 to 770 modern fighters in that year.
Royal Navy gains weren’t needed in a 1938 war, when the Germans had little to nothing to match them.
Except the Gneisenau (the Scharnhorst probably could have been commissioned within a few weeks in a crash program as well), the Deutschland, the Admiral Graf Spee, the Admiral Scheer, the Prinz Eugen, the Blucher, and the Admiral Hipper.
Navy:
1938 - 29 coastal submarines / obsolete and small surface combatants
Obsolete and small surface combatants?
One brand new battleship of 35,000 tons. Six modern heavy cruisers of 12 - 14,000 tones.
The Kriegsmarine's light cruisers were obsolescent, but once you get smaller than that, Germany had over a dozen recent (as in less than five years old) destroyers in service.
All of the new British battleships had little effect during the war, except for patrolling for German raider runs, which almost never came.
Yes, because of the existence of the battleships. If they hadn't been there, the Germans would not have been so constrained.