Nachtjagd by Theo Boiten has this to say about German intruder ops.
The Germans carried out intruder operations in the second half of 1940. They monitored Bomber Command’s daytime radio testing to get prior warning of a night raid, they then planned to operate in three waves.
First to shoot down aircraft as they took off, second to intercept over the North Sea outbound and inbound, and third over the bases as the bombers returned.
They quickly discoved that that it was more profitable to operate only over Bomber Command’s bases when aircraft returned with nav lights on to a lit airfield.
These early sorties were not very successful, during the last five months of 1940 they only shot down eight aircraft, but lost eleven aircraft on operations and another ten to other causes.
This, and increasing number of radar equipped Beaufighters, forced a change in tactics to patrolling over the North Sea, and this was more successful.
However, intruder ops over UK were resumed in 1941 and they extended their area of operations to central England..
Between January to October they claimed 125 RAF aircraft destroyed for their own loss of 55.
The continuing losses, bombing, and strafing forced the RAF to end night flying training in East Anglia, Yorkshire, and Lincolnshire.
It all came to an end in October 1941 when Hitler ordered General Kammhuber to halt all operations over the UK and North Sea.
He gave his reasons as “One cannot expect any results by the Fernnachrjagd.
If the Fernnachrjagd really would have been successful the British would have copied it a long time ago, as they imitate anything that works well”.
Hitler also stated on this occasion “The German citizen, whose house has been destroyed by a British bomber pilot, would rather see the British flyer shot down by a German night fighter in such a way that he can see this British machine lying next to his burning house”.
Hitler also did not believe in the effectiveness of the intruder ops because there had been no noticeable decline in Bomber Command raids on targets in the Reich.