I've also had a 'play' with the sky and I think,on reflection,the original is not too bad.The lighting [and touch of haze] is such that trying to replace it with something more 'interesting' whilst remaining natural looking would require taking the 'new' sky shot in very similar conditions.Not that I would do that anyway of course

.Ok,so I might if it looked real and 'right'.And I had the photoshop skills.Oh dear,am I on the slppery slope here?