Great pair of photos with the quite rare sight of McAlpine's original hangar, which has only recently been knocked down.
Looking at the Luton Corporation hangar I know it was extended at its rear, which can be seen in the second photo, as the roof is a different colour but was this hangar knocked down and rebuilt for Monarch when they moved in or was the hangar again modified as the present hangar, which Monarch eventually vacated has a much higher roof?