Home Forces became concerned about the threat from German paratroopers and AA Command's units were given anti-invasion roles.

A plan to attach groups of riflemen from the infantry training centres to 6 AA Division's widely-spaced S/L sites foundered on the lack of men.

Instead, the S/L detachments themselves were given the responsibility for attacking parachutists before they could organise, and spare men at company HQs were formed into mobile columns using requisitioned civilian transport to hunt them down.

The cluster system was an attempt to improve the chances of picking up enemy bombers and keeping them illuminated for engagement by AA guns or Royal Air Force (RAF) Night fighters.

[16][17][18][19][20] The regiment supplied a cadre of experienced officers and men to 236th S/L Training Rgt at Oswestry where it provided the basis for a new 533 S/L Bty formed on 14 November 1940.

[25][26][27][28] By mid-1943, AA Command was being forced to release manpower for overseas service, particularly Operation Overlord (the planned Allied invasion of Normandy) and most S/L regiments lost one of their four batteries; 347 S/L Bty was disbanded on 5 July 1943.

The AA resources in SE England were strongly reinforced in Operation Diver, but the LAA batteries found these small, fast-moving targets hard to engage.

[31] A lull in the V-1 attacks saw renewed pressure on AA Command to release men for 21st Army Group fighting in North West Europe, and 73rd (Kent Fortress) S/L Rgt was among the regiments that were lost, passing into suspended animation at Braunton in North Devon on 23 September 1944 and completing the process by 3 March 1945.