EU referendum, brexit and the aftermath

Equally, it is hard to know whether they wouldn't have brought more of the economic aims back had they survived longer.

I'm guessing by this you mean after 1945. You should look into the Night of the Long Knives to put things into a context. Yes, there was a 'red-brown' element to Nazism, but it was only one strand. As has been said, however, calling yourself something isn't the same thing as actually being something. The conclusions of the Nazi project ran, in numerous ways, counter to the aims of the Enlightenment- seeking a return to the world before 1798. Regardless of what they called themselves, what they were trying to achieve ran (and runs) counter to any definition of socialism. August Bebel described the anti-semitism that was a component of it as 'socialism of the fools'- you can't seek to liberate a section of the working class at the expense of another.

@Oliver Schick I think out the window is too strong when you look at some of their social policies (and a very small number of economic ones).

If you could say which ones you're thinking of it would probably be better to discuss the specifics. However, generally, the Nazis were quite happy at first to let some already ongoing policies run and claim credit for them, e.g. motorway-building--ironically, the first German motorway, in all but name, had actually been opened by none other than Konrad Adenauer, when he was mayor of Cologne, not by Hitler as propaganda then claimed. There were also other economic stimulus policies being pursued (Germany having been hit very hard by the Great Depression, of course), but none of them had anything to do with the Nazis--as has often been said, had Germany just had a little more time before the German nationalist parties caved in, the Nazis would have disappeared again. When the Nazis had got their wish to control virtually all areas of government and started to implement 'their' policies, they managed to wreck the fledgling German recovery within a few years.

But they were clearly flexible on many "beliefs".

Well, yes, as mentioned about 'socialism', but the cornerstones of Nazi ideology were set in stone in "Mein Kampf", having been formed in Hitler's muddled mind much earlier, partly through his rubbish reading. (Some of what you see on the Internet these days seems very strongly reminiscent of some of his sources.) He was famously inflexible on these.

Equally, it is hard to know whether they wouldn't have brought more of the economic aims back had they survived longer.

Well, of course a massive amount of analysis has been devoted to questions like this, and it's impossible to read it all. My own personal view is that this is very strongly bound up with Hitler's personality, who as a political hasardeur was essentially on a self-destructive course that could only fail. The war was, from the Nazis' perspective, inevitable, because of the nonsensical and inhuman "Blut und Boden" ideology and its implications, and much of Germany's economic efforts in the late 30s were concentrated around the production of armaments, which weakened the country immensely. Food was rationed early on, I think 1938 or 1939, certainly before the outbreak of war, all in order to prepare the war, which was in the works years before it actually started. Nothing that the Nazis' did was aimed at bringing about socialist outcomes, and, discounting untruthful propaganda, I'm certain that nothing that they said in these times can be construed as 'socialist'. Whether or not they might have brought 'socialism' back had they not become embroiled in a world war they couldn't win is a moot point. Hitler mainly relied on Germany's large industrial powers in preparing the war, and there's no reason to think that this reliance would have changed had there been a Nazi Germany after the war. As I said, it's a moot point, as total collapse was inevitable after 1942 at the latest.