By December , 502 Bty had been detached from 149 LAA Rgt .
By December , 502 Bty had been was deployed under 74th AA Bde to guard the vital bridges at Nijmegen , Grave and Mook .
By December , 502 Bty had been detached from 149 LAA Rgt and was deployed under 74th AA Bde to guard the vital bridges at Nijmegen , Grave and Mook .