[2][3][4][5][6][7] The divisional headquarters (HQ) was at Cardiff and the General Officer Commanding (GOC) was Major-General Douglas Paige, MC, who had been commander, Corps Royal Artillery, of XI Corps.<[8][9] The division formed part of I AA Corps, which was created at the same time to cover Southern England and Wales.

[10][12] Of the formations and units assigned to the new division, a number had served with the British Expeditionary Force in the Battle of France and had been reformed and re-equipped in the Severn Valley and West Wales after the Dunkirk evacuation.

There were major concentrations of HAA guns in the Gun Defence Areas (GDAs) at Cardiff (covering Barry, Cardiff, and Newport) and Swansea (covering Llanelli, Port Talbot, and Swansea), LAA units were distributed to defend Vulnerable Points (VPs) such as docks and Glascoed Royal Ordnance Factory, while the S/L detachments were widely spread and crossed brigade boundaries.

[5] On the night of 19/20 February the building housing both the Regimental HQ of the 79th (Hertfordshire Yeomanry) HAA Rgt and the Gun Operations Room (GOR) of the 61st AA Brigade at Swansea was destroyed by a bomb during a heavy raid.

Two officers and five other ranks were killed or died of wounds, but the guns continued firing under local control and communications were maintained.

The HAA and support units increasingly became 'Mixed', indicating that women of the Auxiliary Territorial Service (ATS) were fully integrated into them.

At the same time, experienced units were posted away to train for service overseas (sometimes being lent back to AA Command while awaiting embarkation).

[56] During this period the division was composed as follows:[11][57][55][58] 61st AA Brigade The increased sophistication of Operations Rooms and communications was reflected in the growth in support units, which attained the following organisation by June 1942:[55] The RAOC companies became part of the new Royal Electrical and Mechanical Engineers (REME) during 1942.