The lessons supposedly learned at Dieppe could just as easily have been learned by experiments and exercises on UKbeaches. What the Armies had for experiments and research in combined operations I don't know, but the Admiralty had a thriving Department of Miscellaneous Weapon Development, headed by a Canadian
as a matter of fact: Cmdr. Goodeve. They came up with weapons like the Hedgehog.
As in WWI where the Navy with Churchill as 1st Lord, pioneered the tank regardless of the Army's lack of interest, so in WWII. For example, Goodeve & Co. got to Churchill through his daughter and once WSC saw a demonstration of Hedgehog, he got on the phone to Dudley Pound and suddenly the Admiralty was all in, despite their previous lack of interest and the obstruction of the Directorate of Naval Ordnance.
But in 1942 what was needed was a good flop to show Stalin and the Americans it wasn't as easy as they thought and to get them both to back off.
Now, they say we should not ascribe to malfeasance what can be explained by mere stupidity, and we saw enough of that in both wars, but the curious violations of security and numerous other odd oversights lead me to suspect that "disaster" was a prospect not viewed with, shall we say, any great concern in the highest quarters.
This was total war, a game played for high stakes and sacrifices must be made, sometimes large ones.
The only rub comes in who is asked to make them, and whether they are truly necessary or merely convenient?
And as for the Ultra aspect, the only possible course that would have made sense was to quickly examine and photograph a machine, ensuring there were no Germanor French
witnesses who might notice any interest, and then to leave it strictly as found, as though it had been overlooked completely or was unrecognized.
Of course, to send a group of commandos to attack such a facility as a special sub-raid would immediately indicate what their objective in such an attack was, unless some other piece of technology such as a radar installation was in the same immediate area and could be made to look like the real target.
The supposed commando "snatch" raid on the local Kriegsmarine HQ would have been completely obvious to the Germans as having a specific target, and blowing up some rooms or buildings would immediately raise the question of why they were specially targeted and what was being hidden by the demolitions, to say nothing of whether the wrecked machine was found in the debris or not.
Consider: we have a sudden drop in Uboat sinkings when the fourth rotor is introduced - that perhaps could be hidden by other countermeasures and increased efforts to sink Uboats and so make up the difference, but a specific raid targeting an Enigma facility would be very liable to blow the cover of the greatest intelligence coup in history. Fleming may have written good stories, but would anyone have been allowed to gamble with THE WHOLE Ultra Secret in 1942? Nonsense IMHO. Easy to leave a few bits of paper around in the archives later for someone to find though. Heaven knows, enough paper has been taken out of archives without any one much noticing!
One has to remember that a year earlier Crete was allowed to fall rather than tell Freyberg that we had ironclad "Ultra" intelligence of German plans and positions. He was told the information was from an agent in the German HQ in Greece IIRC, and he chose to disregard it as a result.
Lastly, it was only thanks to Churchill bucking the Army "club" that Hobart was brought back from the Chipping Camden Home Guard where he was serving as a corporal. He then trained IIRC the 11th Armoured Division - as he had trained the 7th in Egypt in 1939-40. However, the old boys club wasn't done with him yet, and found every possible excuse to prevent him from actually taking the Division to North Africa and getting a chance to prove himself and his ideas in combat. So he ended up with the 79th Armd. Div. and the "funnies". That much he was allowed to do, with Churchill's help.
That sort of petty vendetta was more important to the Club than the war itself, to say nothing of the lives of their subordinates. They had seen what the Germans had done, but since they weren't competent to do it themselves, they damned well weren't going to let anyone else, least of all 'one of those damn tank fanatics' they'd been squabbling with and obstructing ever since WWI.