Ok so I have checked every single fuse in the fusebox at the end of the dash and all were okay.

Are there other fuses elsewhere to check?

I need some help here . . .

Damp in the wiring maybe...

For something as major as that, try the fuses on top of the battery.

Sounds very similar to a fault I had a few years ago. No fuses blown, no fault codes or anything found. Solved by dealer replacing the whole heating controls module (under warranty at the time and within 24 hours so was well satisfied despite the inconvenience)