Technically they're acceptable; as mentioned some distortion and levelling issues as a result of your shooting position. The exposure is decent, 'though I think a polarizing filter might have given them a little more 'zap'. At the end of the day, there's not a lot to hold the viewer's interest. This sort of image would be fine for an article about the history of the mill; that is as a supplement, but on their own, I don't find them strong enough to hold my attention and interest.
What could you do about this? To be honest, it's hard to say. A lot of times there are subjects that we see that beg to be photographed, but are all but impossible to capture in an interesing way. This is what truly separates the 'shooter' from the 'photographer. Make this an exercise for yourself. Go back and make them interesting. Perhaps a triptych of the sign, close-ups of the brick and rusty textures... things like that.
Good luck.
