[Kitty]

he would have been royal artillery or ordnance corps most likely, but anyone spare was rafted in to use AckAck guns. And the reason you cannot find the gun emplacements is because there wasn't really any. sandbags at most piled up around field artillery pieces that were on wheels.

at the time your father was protecting the marshalling yards of Crewe, which came under regular Luftwaffe attack [Kampfgeshwader to be precise]. However they would have had a regular pop at any stray bombers coming over on their way to Chester/Manchester/Liverpool.

if you have been to the area then you will have spotted a ruined castle like structure on a large hill line. That is the folly of Mow Cop, the Kampfgeshwader would use this to line up on in order to make their run-ins to their target. Another temporary AckAck gun emplacement was at a farm on the side of the hill itself. There was also a Meacon site at Mow Cop in order to begin bending the navigational beams the bombers were using.

Your father was under canvas as the AckAcks were sent where needed, and as such were only ever temporary. Permanent gun emplacements for air defences were only really found on military bases.