Modify CalibrateMaps() appropriately re #6821

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge Manually with Master re #6821

This was necessary, because of a delay in completing the testing of ticket #6752.

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge branch 'feature/6821_maps_vary' into develop re #6821

Conflicts:
	Code/Mantid/scripts/Calibration/Examples/TubeCalibDemoMaps_Simple.py

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>