Fair enough, but it’s low-level stuff isn’t it? Hardly like he penetrated Whitehall. I meant ‘real’ as in penetrating the enemy’s intelligence network (Zigzag), deciphering the enemy’s high-level code (Enigma), carrying off a large-scale deception (Mincemeat) or massive signal intercepts (Venona).
'Real' spying IS the low level stuff. The high level penetrations are generally people who are already inside and approach the other side for whatever reason or are seduced by a spymaster to turn traitor. It is rare to infiltrate an agent into an enemy intel organization from the start like with the Cambridge 5.
'Zigzag' (I assume you mean Eddie Chapman) was just someone who volunteered to the Germans to get out of prison without any intention of being a spy. That wasn't penetrating the enemy's network as much as extreme luck for the Brits that the Abwehr was desperate enough to employ the guy and that the guy was willing to defect ASAP to Britain's intel service. Even then that was a radio playback operation, which the Germans did too, most infamously but not limited to:
https://en.wikipedia.org/wiki/Englandspiel
SigInt (i.e. Ultra) isn't spying, it's code breaking (that is unless a spy steals some codes like the Italians did with the US diplomatic codes) and was handled by another organization entirely. And the Germans also did that:
http://chris-intel-corner.blogspot.com/search/label/German codebreakers
https://www.amazon.com/Third-Reich-Listening-codebreaking-1939-45/dp/1472829506
In fact they had important successes against both the Soviet and French codes, the latter probably doomed France:
http://chris-intel-corner.blogspot.com/2014/07/the-french-war-ministrys-fld-code.html
http://chris-intel-corner.blogspot.com/2011/07/german-signals-intelligence-and-battle.html
As to Mincemeat it is very possible that the Abwehr were in on it, since they were the ones to report it and immediately labelled all the 'intelligence' as 'above reproach'. Plus the impact was not nearly as important as the Brits claimed, James Hayward, the author I mentioned in the OP, lists all the units transferred and makes the case that the broad spectrum of deception efforts running at the same time were what was responsible, not any one operation.
Nothing concrete, but as it happens I’m reading Operation Mincemeat by Ben Macintyre. In it he mentions that the Abwehr had “agents in Soviet Intelligence”, I kind of went from there. I have no full details, I’m afraid.
But, if it turns out they didn’t, it’s one more thing that the Abwehr were terrible at.
The Germans claimed they did, but they seem to have fallen prey to Soviet 'radio playback' efforts that were every bit if not even more successful than Double Cross. Post-war analysis by the Allies seems to confirm the Soviet claims, though to some extent they might be exaggerated; it also doesn't help that part of the story has never been confirmed by the Soviets and later Russians, while the Soviet intelligence archives are still locked. Perhaps there were some successful double agents, but we may never know so long as the Soviet archives are locked and that's assuming it was even known to them and/or records were even made after the fact about it assuming they were eventually caught.
Everyone had serious problems penetrating the Soviet intelligence services until later on during the Cold War, when KGB agents started to flip because of dissatisfaction with the system/regime. There were NKVD defections, apparently nearly all to avoid the purges in the 1930s-40s, but none that stayed to spy.