I had my level on the camera I don't think it's tilted maybe the undulating horizon
Well, the level can't be wrong for sure. When I take landscape pictures and I find situations like this I prefer to deceive the viewer choosing which is my horizon, but surely it's my choice. In any case a beautiful image - you have many nice landscapes lately :)
It's a very nice image Giles. Probably with a slightly different composition (not tilted and with the road more visible) you could get an even better result.