First, Britain had plenty of gold/dollars in June 1940 (we aren't interested in OTL 1941)
Second, they aren't going to take over the French orders.
I simply fail to see this 'german economic miracle' post win. They are broke (out of foreign reserves, and owing their own people money). In OTL the held this off for a year or so by rampant looting of the conquered countries. If they do this again (how?) they end up with a collapsing European economy (just as in OTL).
You seem to have them squaring a circle they couldn't manage in OTL. Any reparation money sufficient to bail them out also wrecks the European economies. Catch-22.
Now granted, given enough time you can probably sort this out. But Hitler doesn't HAVE time, Stalin is to his East and getting stronger every day.
Define plenty of dollars/gold. Certainly they would have more than they had by January 1941. And yes they couldn't blow it hard in the second half of 1940, so would have reserves for a measured recovery after June 1940...but that measured recovery would take longer to implement.
Also I'm not arguing for an 'economic miracle', just the return to a peace time economy for Europe without the blockade, but with German in control over an economic zone that had a combined GDP higher than the US in 1940 not counting their empires. The German took effectively hundreds of millions of dollars of 1940 value gold from all over Europe IOTL, not counting occupation reimbursements which totals billions of dollars in value, without even counting what they would do with access to all the French, Dutch, Belgian gold in US banks or abroad. End the blockade, restore access to imperial imports/exports, restore German corporate access to Latin American/North American profits (tens if not hundreds of millions of dollars worth of profits in foreign currencies they were cut off from IOTL and was confiscated by the US during and at the end of the war), and remove the need to keep spending for the Germans on a war against Britain means a lot more money coming in, a lot less going out on war expenditures.
Remember even in 1941 during Barbarossa over half of German war spending was going to fight Britain NOT the USSR; in fact the military budget allocated to procurement of items to fight the war in the East was never more than less than half the military budget. If the Germans don't go to war with the USSR and instead demobilize they have all the bridge money they need to convert to a non-militarized economy, plus the captive markets of Europe.
Granted Nazi planning was not the best, but they have a very large economic cushion to transition and no need to rearm like the Brits. Plus they've eliminated all their continental enemies for the foreseeable future (the USSR is not going to attack a Nazi Germany at peace with Britain). The question is what lasting system would be created. There were a number of proposals for a common market and with peace in 1940 it is open to discussion what form that would have taken; it does seem that the longer the war went on IOTL the more radical Hitler and his inner circle got about German hegemony on the continent, so an earlier peace might moderate what actual happens vs. where Hitler was at in 1943 and later, especially if the USSR is not invaded. If there was peace in 1940 there is a chance Hitler might not turn East, as many of the triggering events to convince him that Stalin couldn't be trusted came after July 1940, which would ITTL be after the POD and could be butterflied away. As of August 1940 at very least Barbarossa was not decided on, IIRC the decision being made for sure late in 1940 or very early in 1941. Plus without an ongoing war Hitler might well feel he doesn't have the domestic political cover to go to war, he apparently remarked during the war he feared that with victory over Britain he wouldn't be able to rouse the German people to go to war again.
Pissed at losing, certainly. But Labour fought rearmament to the bitter end, this isn't going to be waved away as you think. And the Tories will certainly be reminding the electorate.
I simply fail to see why losing, hence obviously not preparing enough, makes people vote for the party that regularly, repeatedly and fervently opposed preparing for war. Have the Germans been lacing the reservoirs with lead paint again?
The Brits were happy to dump Churchill the first chance they got in 1945.