Hi Martyn. Welcome to justanswer.
Is it happening with only one lens or all the lenses?
Have you checked the photos in the computer? Is the haze still there?
How did things turn out Martyn
Try resetting the camera to factory settings.
Check this image and locate the Setup tab 3.
Your camera is EOS 1200D right?
Set the camera is Creative Zone mode and then press the menu
When you press Menu, let me know how many tabs are there?
Let me know the dial is set to which mode?
Martyn, are you there?